Miscellanea 655 ANNALS OF GEOPHYSICS, VOL. 51, N. 4 August 2008 Key words Etna – Stromboli – Vulcano – eruption, and earthquake 1. Introduction Earthquake-eruption and eruption-eruption triggering mechanisms are the subject of in- tense debate and represent the new frontier for several geophysicists and volcanologists (Kanamori and Givens, 1982; Kimura, 1996; Brodsky et al., 1998, 2000; Gudmundsson and Brenner, 2003; Marzocchi et al., 2004; Gud- mundsson, 2006; Feuillet et al., 2006; Madonia et al., 2008). In recent years, a few case histo- ries of eruptions that triggered earthquakes (Jacques et al., 1996; Azzaro et al., 2001; Wal- ter and Amelung, 2006) or other eruptions (Miklius and Cervelli, 2003; Gudmundsson and Andrew, 2007), and of eruptions that hindered earthquakes (Walter and Amelung, 2004) have been reported. In contrast, several case histories of large earthquakes that triggered eruptions at near or remote volcanoes are now well docu- mented (Carr, 1977; Marzocchi et al., 1993, 2002, 2004; Barrientos, 1994; Linde and Sacks, 1998; Nostro et al., 1998; Manga and Brodsky, 2006; Cigolini et al., 2007; Harris and Ripepe, 2007; Lemarchand and Grasso, 2007; Manga, 2007; Mellors et al., 2007; Walter and Amelung, 2007; Walter et al., 2007). Eruptions triggering other eruptions at the Southern Italian volcanoes (i.e., Etna and Aeo- lian volcanoes, fig. 1) have been speculated since at least the 1st Century BC (Diodorus Concurrent eruptions at Etna, Stromboli, and Vulcano: casualty or causality? Andrea Billi and Renato Funiciello Dipartimento di Scienze Geologiche, Università «Roma Tre», Roma, Italy Abstract Anecdotes of concurrent eruptions at Etna, Stromboli, and Vulcano (Southern Italy) have persisted for more than 2000 years and volcanologists in recent and past times have hypothesized a causal link among these volcanoes. Here this hypothesis is tested. To introduce the problem and provide examples of the type of expected volcanic phenomena, narratives of the most notable examples of concurrent eruptions are provided. Then the frequency of eruptions at each individual volcano is analysed for about the last 300 years and the expected probability of concurrent eruptions is calculated to compare it to the observed probability. Results show that the occurrence of concurrent eruptions is often more frequent than a random probability, particularly for the Stromboli-Vulcano pair. These results are integrated with a statistical analysis of the earthquake catalogue to find evidence of linked seismicity in the Etnean and Aeolian areas. Results suggest a moderate incidence of non-random concurrent eruptions, but available data are temporally limited and do not allow an unequivocal identification of plausible triggers; our results, however, are the first attempt to quantify a more-than-2000-years-old curious observation and constitute a starting point for more sophisticated analyses of new data in the future. We look forward to our prediction of a moderate incidence of concurrent eruptions being confirmed or refuted with the passage of time and occurrence of new events. Mailing address: Andrea Billi, Dipartimento di Scien- ze Geologiche, Università «Roma Tre», Largo S. L. Murial- do 1, 00146 Roma, Italy; tel: +39 0657338016; fax: +39 0657338201; e-mail: billi@uniroma3.it Miscellanea 9-03-2009 14:42 Pagina 655 656 A. Billi and R. Funiciello Siculus in Bibliotheca Historica). Julius Solinus (in Collectanea Rerum Memorabilium, 4th Cen- tury AD) wrote that there should have been sub- terranean conduits that linked and fed these vol- canoes. de Dolomieu (1783) also hypothesized direct feeding relationships between Etna and the Aeolian volcanoes, whereas Mercalli (1879, 1888) supposed an indirect physical (i.e., dy- namic) link between these volcanoes. Recently, Cigolini et al. (2007) provided evidence of linked volcanic phenomena at Etna and Aeolian volcanoes during 2002-2003. Although Southern Italy is seismically ac- tive and several M≥7 earthquakes were record- ed in historical times (Boschi et al., 1997; Neri et al., 2006; Basili et al., 2008), eruptions at Et- na, Stromboli, and Vulcano triggered by large nearby earthquakes are not known. In particu- lar, the six largest historical earthquakes (with epicentral MCS intensity≥IX) of eastern Sicily and southern Calabria (fig. 1) were not shortly followed by significant eruptions from the near- by volcanoes (table I), which, therefore, pro- vide valuable case histories to study eruption triggers alternative to large nearby earthquakes (Sharp et al., 1981). This paper searches for evidence for a link between eruptions at Etna, Stromboli, and Vul- cano. Our hypothesis is that concurrent activity at these volcanoes may occur at a frequency higher than expected based on the background rate. This hypothesis is explored in three differ- ent ways. The eruption catalogue is statistically analysed. The statistical method has the advan- tage of being quantitative, but the disadvantage of providing little insight into the plethora of behaviour that can fall under the heading of eruption. To fill out this story and provide ex- amples of the type of phenomena expected, nar- ratives of the most notable examples of concur- rent activity are provided. Finally, the catalogue of instrumentally-recorded earthquakes is analysed to find evidence of linked seismicity in the Etnean and Aeolian areas. This paper ex- tends previous studies on analogous subjects (e.g., Mulargia et al. 1985; Nercessian et al., 1991; Cardaci et al., 1993). Moreover, the prob- lem of possible links between concurrent erup- tions at nearby volcanoes has been previously studied in other regions (e.g., Klein, 1982; Beb- bington and Lai, 1996). 2. Geological setting Etna and Aeolian volcanoes (fig. 1) are lo- cated along the active convergent margin be- tween the African and Eurasian plates in the central Mediterranean region (Malinverno and Ryan, 1986). A narrow remnant of the Ionian Table I. Largest historical earthquakes of Sicily and southern Calabria (southern Italy, fig. 1) and subsequent eruptions at Etna, Stromboli, and Vulcano. Data are from Simkin and Siebert (1994) and from Boschi et al. (1997). earthquake date epicentral MCS intensity epicentral area subsequent eruptions 4 Feb. 1169 XI Estern Sicily and a doubtful eruption western Calabria from Etna on Feb. 1169 10 Dec. 1542 IX-X Southeastern Sicily none 11 Jan. 1693 XI Southeastern Sicily none 5 Mar. 1823 X Northeastern Sicily none 28 Dec. 1908 XI Messina Straits none 15 Oct. 1911 X Southeastern flank of Mt Etna none Miscellanea 9-03-2009 14:42 Pagina 656 657 Concurrent eruptions at Etna, Stromboli, and Vulcano: casualty or casuality? ��������������������������� ��� ������ ������ ������ ������������������������ ���������� ��� ������ ��� ��������������� ��� ������ ��������� ������ ������������������ � � �� � �� � � � �� � �� � � � �� � �� � � �� �� �� �� �� �� �� � �� �� �� �� �� �� �� � �� �� �� �� �� �� �� � ������� �� ��� ��� � � �� � �!� �!� �! ������������ "������"������"������ ������������������ �� � �� � �� � �� �� � # �� � � # �� � � # �� � $������� $������� $������� ��������%������� ��������%������� ��������%������� ������������������������������ ��������������������� ��������������� ��������������������� ������ ������ ���������&���������&���������& �������$�����������$�����������$���� ���������' ���������' ���������' � ��� ��� �� ( �!( �!( �! ��������������� ��������������� # ���# ���# ��� � ��������������������� � � �� �� �� �� �� �� �� � �� �� � � � �� �� �� �� �� �� �� � �� �� � � � �� �� �� �� �� �� �� � �� �� � ��&����������&����������&�������� ������������ )���)���)��� "������"������"������ ��������������������������������������������������������� � �� �� �� � � �� �� �� � � �� �� �� � *������*������*������ +�$���+�$���+�$��� , �� � , �� � , �� � ��������������������� ��������������� -�. -�. Fig. 1a,b. (a) Tectonic map of Southern Italy. Main fold-thrust belts occurring along the African-European plate boundary (i.e., Apennines, Calabrian Arc, and Maghrebides) are drawn in red. (b) Hillshade of north-eastern Sicily, including the studied volcanoes (i.e., Etna, Stromboli, and Vulcano). Note that Stromboli and Vulcano are included in the Aeolian Archipelago. Earthquake focal mechanisms (M ≥ 3.5) and arrows indicating active stresses are from Neri et al. (2005). Miscellanea 9-03-2009 14:42 Pagina 657 658 A. Billi and R. Funiciello slab (African affinity) is subducting toward the northwest beneath the Calabrian Arc, whereas large slab windows occur beneath Sicily and the southern Apennines, where subduction is most- ly inactive (Gvirtzman and Nur, 2001; Faccenna et al., 2004, 2005). The Apennine and Maghre- bian thrust-fold belt have grown since late Pale- ogene time along the Africa-Eurasia suture zone, with eastward and southward vergence, respectively. To the north of Sicily, the oceanic Tyrrhenian backarc basin started to form since about late Neogene time (Malinverno and Ryan, 1986; Dewey et al., 1989; Patacca et al., 1992). Seismic and geodetic evidence from Sicily and surrounding regions shows that, in the cen- tral Mediterranean region, Africa and Eurasia are converging at a considerable rate (circa 3 mm/yr) and that both the Etnean and Aeolian areas are undergoing N-S-oriented tectonic compression (fig. 1b; Barberi et al., 2000; Neri et al., 2003, 2005; D’Agostino and Selvaggi, 2004; Goes et al., 2004; Montone et al., 2004; Pondrelli et al., 2004). In the study area, main active tectonic elements are the roughly E-W- trending thrust belt in the southern Tyrrhenian area and the NNW-striking Tindari Fault be- tween the Aeolian Islands and Mount Etna (fig. 1). The compressional belt in the southern Tyrrhenian area accommodates most of the Africa-Eurasia ongoing convergence in the cen- tral Mediterranean area and is characterized by compressional and transpressional earthquakes with a maximum recorded magnitude of 5.9 (Goes et al., 2004; Billi et al., 2007). This belt involves the western islands of the Aeolian Archipelago, i.e., Alicudi and Filicudi, which are the summit of submarine volcanoes inactive since about mid-Pleistocene time. The Tindari Fault is the eastern boundary of the south- Tyrrhenian compressional belt and is character- ized by right-lateral strike-slip earthquakes with a maximum recorded magnitude of 5.5. This fault involves the central islands of the Aeolian Archipelago (Salina, Lipari, and Vulcano) and extends toward the south near Mount Etna (Ghisetti, 1979; Tortorici et al., 1995; Ventura et al., 1999; Billi et al., 2006). The Aeolian volcanoes (Alicudi, Filicudi, Lipari, Panarea, Salina, Stromboli, and Vulcano, fig. 1) form a high-K calc-alkaline island arc, whose activity started about 1.3 Myr ago and is still active on at least three of the seven major is- lands, namely Lipari (last eruption in 729), Vul- cano (last eruptions in 1888-1892), and Strom- boli (Simkin and Siebert, 1994; Behncke, 2001). Hydrothermal activity offshore Panarea has oc- curred in historical times and in recent years (e.g., Gabbianelli et al., 1993; Esposito et al., 2006). Stromboli is characterized by a persistent volcanic activity consisting in continuous small explosions occurring at approximately regular intervals of a few minutes (i.e., strombolian ac- tivity). However, individual events, such as lava effusions and paroxysmal eruptions, occurred at Stromboli during recent and historical times (Rittmann, 1931; Simkin and Siebert, 1994). The volcanic activity of Vulcano has been char- acterized by powerful and impressive explo- sions (i.e., vulcanian eruptions) alternated with less frequent effusive events (Frazzetta et al., 1984; Simkin and Siebert, 1994). Volcanism in the Etnean area started about 0.5 Myr ago with tholeiitic magmas (Branca et al., 2008). The modern volcano formed by a succession of volcanic edifices consisting in al- ternating pyroclastic and effusive rocks (Gillot et al., 1994; Behncke, 2001; Tanguy et al., 2007; Branca et al., 2008). The volcanic activi- ty of Etna is, in fact, mostly effusive; however, explosive activity has often occurred at the summit craters (e.g., Simkin and Siebert, 1994). Lateral effusive and mildly explosive eruptions have also been frequent at Mount Etna (Rittmann, 1964; Lanzafame et al., 2003; Al- parone et al., 2005). The source of Etna mag- matism is possibly connected with a mantle plume that Montelli et al. (2004) imaged above 1000 km using seismic tomography. Alterna- tively or complementarily, the voluminous melting under Mount Etna may result from suc- tion of asthenospheric material induced by the backward migration of the descending Ionian slab (Gvirtzman and Nur, 1999). 3. Examples of concurrent eruptions Eruption catalogues are notoriously subjec- tive. Eruptive activity is gradational and activi- ty during a given month may mean a variety of Miscellanea 9-03-2009 14:42 Pagina 658 659 Concurrent eruptions at Etna, Stromboli, and Vulcano: casualty or casuality? different phenomena. To fill out this story, be- fore the statistical analysis of the eruption cata- logue, brief narratives of four of the most no- table examples of concurrent activity are pro- vided. Two of these episodes fall outside our statis- tical study period (see the following section) and three involve observations from another Aeolian volcano (i.e., Panarea), but these sto- ries are anyhow included to provide examples of the type of phenomena expected. The acronym VEI is henceforth used in- stead of volcanic explosivity index (Newhall and Self, 1982) and the related values are from Simkin and Siebert (1994). 3.1. Concurrent activity during 2002-2003 The 2002 eruption of Etna started the night between 26 and 27 October 2002 from the sum- mit craters, concurrently with the formation of ground-surface fractures in this area. From the summit craters, fractures propagated toward the south and toward the northeast. Newly generated vents and cones developed along these fractures. For about two months since the onset of the eruption, voluminous emissions of ash oc- curred. Volcanic ashes fell in the nearby regions of Sicily and Calabria. After about 95 days of almost continuous eruption, on 29 January 2003, Etna ceased most of its effusive and ex- plosive activity. The 2002-2003 eruption of Etna was highly explosive, possibly one of the most explosive of the last 350 years. Early in the morning of 3 November 2002, local fishermen observed spots of anomalous seawater boiling and high mortality of fishes offshore Panarea, and perceived smell of sul- phurs. In particular, five major sites of gas emissions were found around the islets of Lisca Bianca, Bottaro, and Lisca Nera. At these sites, ascent of gas bubbles with diameter up to 1 m on the sea surface signalled the presence of sub- marine gas-emissions. With the exception of one site close to Lisca Bianca, these sites were previously unknown as gas-emitting spots. Gas emissions originated from NW- and NE-strik- ing fractures in volcanic rocks lying at depths between 8 and 30 m from the sea surface. Gas emissions offshore Panarea gradually ceased during the first months of 2003. On 28 December 2002, after 17 years of mild although continuous volcanic activity, an intense eruption began at Stromboli. The erup- tion was preceded by seismic swarms and by an increase in volcanic tremors since 3 November 2002, concurrently with the onset of gas emis- sions offshore Panarea. Since 28 December 2002, lava flowed from the Stromboli summit crater into the sea along the steep northwest flank. Renewed lava flow occurred since 30 December 2002. The erup- tion mostly ceased by 5 April 2003, when a powerful explosion occurred at the summit crater of Stromboli. The above information is mostly synthe- sized after Acocella et al. (2003); Dellino and Kyriakopoulos (2003); Patanè et al. (2003); Caliro et al. (2004); Calvari et al. (2005); Ripepe et al. (2005); Walter et al. (2005); Es- posito et al. (2006), and Cigolini et al. (2007). 3.2. Concurrent activity during 1886-1890 From 10 January to 31 March 1886, strom- bolian activity occurred at Vulcano. On 22 Jan- uary 1886, volcanic explosions occurred at Stromboli. On 18 May 1886, an eruption began at the summit craters of Mount Etna. This erup- tion was highly explosive (VEI = 3). During January, March, and November 1887, volcanic explosions occurred at Strom- boli. On 3 August 1888, an eruption began at Vulcano. The eruptive activity of Vulcano ceased in March 1990. The 1888-1890 eruption of Vul- cano was highly explosive (VEI = 3). On 23 October 1888, volcanic explosions and lava fountains occurred at Stromboli. On 29 Novem- ber 1888, offshore Vulcano, local fishermen ob- served boiling seawater and associated fish mortality, and perceived smell of sulphurs. The above information are mostly synthe- sized after Mercalli (1888); Silvestri (1890, 1893); Baratta (1901) and Simkin and Siebert (1994). Miscellanea 9-03-2009 14:42 Pagina 659 660 A. Billi and R. Funiciello 3.3. Concurrent activity during 1865 On 30 January 1865, an explosive (VEI≥2) eruption occurred at Etna. At the onset of the eruption, NE-striking fractures propagated across the summit crater of Mount Etna. Sever- al vents and cones formed along these fractures. The effusive and explosive activity at Mount Et- na lasted for about 90 days. Voluminous emis- sions of ash, which fell for about two months in the nearby regions of Sicily and Calabria, ac- companied the eruption from the beginning. During the 1865 eruption of Etna, emissions of sulphurous gases occurred offshore Panarea. From 26 January to 2 February 1865, volcanic explosions occurred at Stromboli. The above information is mostly synthesized after Fouqué (1865); Silvestri (1867); Mercalli (1879, 1888); Baratta (1901), and Simkin and Siebert (1994). Most volcanic phenomena oc- curred at Etna and Aeolian volcanoes during 1865 are incredibly very similar to those oc- curred at the same volcanoes during 2002-2003. 3.4. Concurrent activity during 126 BC Paulus Orosius, a Latin historian lived in the 5th Century. In his Historiarum Adversus Paganos wrote: «Under the consulate of M. Aemilius Laepidus and L. Orestes, Mount Etna was violently shaken by a powerful tremble and poured out waves of fire globes. The day after, the Lipari Islands (i.e., also known as Aeolian Islands) and nearby the sea reached such a high boiling point that rocks were burnt and broken up. Ships, axes, and wax were carbonized and melted, dead fishes were burnt on the sea sur- face, and several men, except those who were able to escape, were stifled and their inner or- gans burnt by breathing». Strabo, a Greek geog- rapher, and Julius Obsequens, a Latin historian, had reported the same event in documents dat- ed back to the 1st Century BC (Geographia) and to the 4th Century (De Prodigiis), respectively. The events reported by the above-cited authors refer to the explosive eruption of Mount Etna started in June 126 BC and to the contempora- neous emissions of gas occurred in the offshore area between Vulcano and Panarea. 4. Statistical analysis of the eruption catalogue This section analyses the historical frequen- cy of simultaneous eruptions at two or three volcanoes among Etna, Stromboli, and Vul- cano. The analysed catalogue is the one com- piled by Simkin and Siebert (1994). We pre- ferred to use the printed version of this cata- logue (Simkin and Siebert, 1994) rather than the online version available at www.volcano.si.edu, because this latter is a non-static document updated in subsequent years (Siebert and Simkin, 2002), where, how- ever, reasons for amendments are not ex- plained, at least for what concerns the studied volcanoes. The problem of possible errors con- tained in the historical catalogue is addressed below in the discussion section. As eruptions are often ongoing sequences of various and heterogeneous phenomena (see the preceding section), the problem studied here is simply whether or not eruptions at Etna, Strom- boli, and Vulcano overlapped more often than expected by chance. This means that we do not consider eruption onset, whose exact dates are often lacking of poorly constrained (Simkin and Siebert, 1994). Instead, we analyse eruption du- rations, that is whether an eruption is in progress at some point in a specific time inter- val. To do so, simultaneous months and years including eruptions at two or three of the stud- ied volcanoes are considered (tables III and IV). The analysis does not attempt to distinguish be- tween eruptive styles or locations within a giv- en volcanic system. This leaves the eruptive triggers poorly constrained, but makes the sta- tistics possible for the historical data. A null hypothesis can be constructed by us- ing the observed record (tables III and IV) to calculate the expected probability of concurrent eruptions if the volcanoes do not interact. For instance, if the observed historical probability of Etna erupting in a given month or year (pE) is the number of months or years including Et- na’s eruptions divided by the total number of months or years included in the studied period, and the observed historical probability of Stromboli (pS) is computed in the same manner, then the expected historical probability (or ex- Miscellanea 9-03-2009 14:42 Pagina 660 661 Concurrent eruptions at Etna, Stromboli, and Vulcano: casualty or casuality? pected probability) of concurrent eruptions at Etna and Stromboli pE-S is simply the product pE pS. In this section, the null hypothesis that erup- tions at each of the volcanoes are statistically independent is evaluated by calculating the ex- pected probability of concurrent eruptions (e.g., pE pS) at two or three volcanoes among Etna, Stromboli, and Vulcano and by comparing it to the observed probability of concurrent erup- tions. Before evaluating the probabilities, the cat- alogue is limited by type of data and by time to provide uniform completeness over the study interval. The catalogue is expected to be com- plete for the largest, most easily observable eruptions, but progressively more incomplete at the smaller sizes. Volcanic eruptions generally follow a power law distribution in sizes with many more small eruptions than large ones as quantified by VEI. Significant depressions at small VEI relative to the trend at large VEI sug- gest that there are missing eruptions in the cat- alogue. Figure 2 suggests that the volcanic cat- alogue used for this region (Simkin and Siebert, 1994) is only complete for about VEI ≥ 2. For this reason, only eruptions with VEI ≥ 2 are used for the analysis. To find the temporal intervals significant for the statistical analysis, the temporal distribution of data (i.e., eruptions) for the studied volca- noes is analysed. The catalogue is significant, by number of data, since about the 18th Century (fig. 3). About 1700 or younger times are there- fore considered as the lower temporal boundary for the following statistical analysis. The limited catalogue is used to estimate the probability of eruption per month and per year of each individual volcano as above explained. Results are plotted in probability versus time diagrams (fig. 4) to check whether the statisti- cal analysis is sensitive to the time window. In each diagram, observed and expected probabil- ities of concurrent eruptions at two volcanoes between Etna, Stromboli, and Vulcano are com- pared. Etna-Vulcano and Stromboli-Vulcano pairs of volcanoes generally erupt simultane- ously more frequently than would be expected based on the individual rates (figs. 4b and 4c). This relationship is particularly evident for the Stromboli-Vulcano pair (fig. 4c). In contrast, the simultaneous eruptions of Etna and Strom- boli are often less frequent than would be ex- pected based on the individual rates (fig. 4a). The expected and observed probabilities of occurrence of simultaneous eruptions at the three studied volcanoes are also considered. Within the 1700-1890 period, the expected probability of a triple eruption is 0.015% by us- ing months as a time period, and 0.400% using years. Within the same period (i.e., 1700-1890), the observed probability of a triple eruption is � ���� ��� �� � � � � *���������/$����0��������/�-*��. ! � � � � �� � %� � �� $ �� � � � �1 �* � � 1� 2�33�� 4 1��� 2� � 4 1�� 2�33�� 4 1�� 2�33�� 4 1�� 2�3 � 4 Fig. 2. Relationship between the number of eruptions and the «magnitude» of the eruption expressed by the volcanic explosivity index (VEI) for Etna, Stromboli, and Vulcano. Data (tables III and IV) are from Simkin and Siebert (1994). Miscellanea 9-03-2009 14:42 Pagina 661 662 A. Billi and R. Funiciello 0.044% by using months as time period, and 1.047% by using years (tables III and IV). It fol- lows that, in both cases, the observed probabili- ty is almost three times the expected probability. It is eventually analysed whether concurrent eruptions often occur in a particular order. Dur- ing the 1700-1993 period, the order of eruption is often Vulcano, Etna, and then Stromboli (ta- bles II and III). If only two of the three erupt, the order is usually preserved. 5. Statistical analysis of the earthquake catalogue To infer possible chronological correlations between the seismic energies released in the Et- nean and Aeolian areas, the related monthly to- tals of seismic moment (TM0) are computed and compared. The problem studied in this section is sim- ply whether or not the greatest TM0-values for the Aeolian and Etnean areas overlapped more often than expected by chance. To do so, the magnitude of earthquakes (i.e., only those less than 30 km deep) occurred in the Aeolian and Etnean areas during the January 1983-Decem- ber 2007 period (i.e., 300 months) is extracted from the INGV catalogue of earthquakes avail- able on-line at www.ingv.it (Bollettino Sismico Italiano, Istituto Nazionale di Geofisica e Vul- canologia, Rome, Italy). Date and geographic location of earthquakes (i.e., Aeolian and Et- nean areas) are included in the catalogue. The � ��� ��� ���� ���� ���� ���� ���� �� ������� �� � � ��� � �� � ���� -�. � �� �� ���� ���� ���� ���� �� ������� �� � � ��� � �� � ��������� -�. � �� �� ��� ��� ���� ���� ���� ���� �� ������� �� � � ��� � �� � *������ -�. Fig. 3a-c. Relationships between the cumulative number of data (i.e., months including eruptions with VEI ≥ 2) and time for (a) Etna, (b) Stromboli, and (c) Vulcano. Data (table III) are from Simkin and Siebert (1994). Table II. Time order of erupting volcanoes in the occasion of duple and triple concurrent eruptions between 1700 and 1993. Data are from Simkin and Siebert (1994). type of concurrent erupting no. of times in which the volcano erupted before eruptions volcanoes the others in theoccasion of concurrent eruptions Etna Stromboli Vulcano duple Etna-Stromboli 23 3 / duple Etna-Vulcano 0 / 4 duple Stromboli-Vulcano / 0 2 triple Etna-Stromboli-Vulcano 0 0 1 Miscellanea 9-03-2009 14:42 Pagina 662 663 Concurrent eruptions at Etna, Stromboli, and Vulcano: casualty or casuality? Fig. 4a-c. Expected and observed probabilities of occurrence of months (diagrams to the left) and years (dia- grams to the right) including concurrent eruptions at (a) Etna and Stromboli, (b) Etna and Vulcano, and (c) Stromboli and Vulcano, versus time. Data (tables III and IV) are from Simkin and Siebert (1994). A rather high correlation of activity is observed in (b) and (c). ��� ���� �� ������� � �� �� �! " " � � ��� �� �# � �$ ����� !"������ % �% ��� ���� � % �! " " � � ��� �� �# � �$ ����� !"�������� �� ������� �% �� ������� �� ������� � �� �� �� �� �! " " � � ��� �� �# � �$ ����� !"������ ��� ���� �� ������� �&% �&� �&% &� &% �&� �! " " � � ��� �� �# � ����2���������-�. �$ ����� !"������ ��� ���� �� ������� � �� �� �! " " � � ��� �� �# � ����2*������-�. �$ ����� !"������ ��� ���� � � �! " " � � ��� �� �# � ���������2*������-�. �$ ����� !"������ � � �� ������� Miscellanea 9-03-2009 14:42 Pagina 663 664 A. Billi and R. Funiciello magnitude of earthquakes is converted into the seismic moment by applying the equation M = 2/3 log M0 – 10.7, where M is the magnitude and M0 is the seismic moment (Hanks and Kanamori, 1979). TM0-values are then comput- ed (table V). By following the same probabilistic ap- proach used above for concurrent eruptions, the expected and observed probabilities that the greatest TM0 of the Aeolian and Etnean areas are contemporary are computed and compared (fig. 5). Figure 5 shows that, except for the two months with the greatest TM0-values (i.e., for no. of months ≥ 2 in fig. 5), the observed prob- ability is always significantly greater than the expected probability. From the eruption catalogues of Simkin and Siebert (1994) and Siebert and Simkin (2002), it is inferred that, both for the Aeolian and Et- nean areas, the greatest TM0-values are, in some cases, contemporary with or near to sig- nificant eruptions (e.g., October 1986, July 2001, October, 2002, and December, 2006 at Etna; November, 1994 and July. 2001 at Strom- boli), whereas in some other cases there is no correlation with eruptions (e.g., December, 1997 and January, 1998 for Etna; October, 1986, July-August, 1995, and April, 2002 for Stromboli). 6. Discussion The statistical analysis of the eruption cata- logue shows that, during 1700-1993, concurrent eruptions at the studied volcanoes occurred, at least in some cases, at a frequency higher than expected based solely on random probability (fig. 4). This result, in particular, applies to the Stromboli-Vulcano and Etna-Vulcano pairs. It follows that concurrent eruptions at these vol- canoes can be plausibly interpreted as non-acci- dental. The considered temporal interval is, however, limited and the statistical analyses may therefore be poorly representative of the real rate of concurrent eruptions. Moreover, sta- tistical results may reflect reporting biases and the analysed catalogues may contain errors. These issues make our results preliminary and our hypotheses very speculative at least in some instances. On the other hand, statistical analy- ses do not consider eruptions with VEI < 2 and a series of volcanic phenomena such as de- gassing, unrest, or hydrothermalism, which are poorly reported in the catalogues but can be the manifestation of linked activities at Etna and Aeolian volcanoes (e.g., Cigolini et al., 2007). It follows that the incidence of concurrent vol- canic phenomena at the studied volcanoes may be greater than that obtained by the statistical analyses presented in this paper. The recent literature on eruption triggering suggests that the cause of concurrent eruptions may be a reciprocal stimulus or an external common one. Among the possible external causes, earthquakes are considered the most common and viable ones (e.g., Linde and Sacks, 1998; Manga and Brodsky, 2006). Earth- quakes may trigger volcanic eruptions by dy- namic stress (i.e., the shaking of rocks at the passage of seismic waves; e.g., Walter and Amelung, 2007). In addition to dynamic stress, fault slip induces a static stress change (i.e., the fault slip induces a permanent deformation in the nearby crust), which can be at the origin of volcanic eruptions (e.g., Bautista et al., 1996; Nostro et al., 1998). In the first case (i.e., dy- namic stress), the earthquake and the volcano can even be very far (e.g., Manga and Brodsky, 2006). In contrast, the effect of the fault-related static stress change decays rapidly with the dis- tance and, therefore, the fault has to be near the volcano to efficiently excite it. In addition to earthquakes and fault slip, the stress changes induced by the annual sea-level variations (McNutt and Beavan, 1987), by the Earth and ocean daily tides (Glasby and Kasa- hara, 2001), the glacial loading (Tryggvasson, 1973), by the seasonal atmospheric variations (Ohtake and Nakahara, 1999), and by the re- gional tectonics (Mulargia et al., 1991; McNutt, 1999; Madonia et al., 2008) have been hypoth- esized as potential external triggers of volcanic eruptions. Alternatively or complementarily, eruptions can reciprocally trigger other events. Either the static stress generated by the movement of magma (Miklius and Cervelli, 2003; Gud- mundsson and Andrew, 2007) or the shaking generated by explosive eruptions and associat- Miscellanea 9-03-2009 14:42 Pagina 664 665 Concurrent eruptions at Etna, Stromboli, and Vulcano: casualty or casuality? ed earthquakes (Kanamori and Givens, 1982) can trigger adjacent volcanoes. Eventually, concurrent eruptions from adja- cent volcanoes can be triggered by a simultane- ous increase of magma supply from the mantle (Miklius and Cervelli, 2003). The presented statistical and anecdotal evi- dence of concurrent activities at Etna, Strom- boli, and Vulcano does not allow an unequivo- cal identification of a plausible triggering mechanism. It cannot even be discounted the idea that the triggering mechanism may have changed from time to time or may have been a combination of the above-quoted triggering mechanisms. Some simple inferences can, how- ever, be drawn from the presented evidence. The sequential order of eruptions (table II) sug- gests that eruption-eruption reciprocal trigger- ing may have been important. As Vulcano was often the most explosive of the volcanoes (Simkin and Siebert, 1994; tables III and IV), it likely generated the strongest seismic waves and hence usually began the sequence (table II). The vicinity of Vulcano to both Etna and Stromboli (fig. 1) may explain why its relation- ships with these volcanoes are seemingly causal (figs. 4b and 4c), whereas concurrent activities at Etna and Stromboli, which are as far as about 130 km, seem accidental or less connected (fig. 4a). The presence of an active fault zone be- tween Vulcano and Etna (i.e., the Tindari Fault, fig. 1) may have enhanced the directivity of seismic waves between these volcanoes, thus promoting the dynamic stress transfer. Of � # � ( � # � ( $ �� � � � �� �� �� � �- 5 . ��'��%������� !"������ �!" "� ��� �$ ����� �!" "� ��� Fig. 5. Expected and observed probabilities of concurrence of months with the greatest monthly totals of seis- mic moment (TM0) for the Aeolian and Etnean areas (table V). For a number of months greater than 45, the di- vergence between the expected and observed probabilities increases. Miscellanea 9-03-2009 14:42 Pagina 665 666 A. Billi and R. Funiciello course, whether or not a given dynamic input successfully triggers an eruption depends on the state of the volcano, particularly its magma chamber. Accordingly, it is not expected to ob- serve perfect correlations or a deterministic se- quence of eruptions. A reciprocal triggering similar to that pro- posed for Iceland volcanoes (i.e., by direct me- chanical interactions among volcanoes about 30 km distant; Gudmundsson and Andrew, 2007) seems less likely for the studied volcanoes, whose reciprocal distance is as small as 50 km (fig. 1). However, as shown by the reported an- ecdotal instances, the concurrent volcanic phe- nomena can be very heterogeneous and can in- volve other volcanoes in addition to Etna, Stromboli, and Vulcano. For instance, in- creased degassing from Panarea, which is only about 22 km from Stromboli and 30 km from Vulcano, may have been the consequence of di- rect mechanical interactions with the adjacent active volcanoes (e.g., Gudmundsson and An- drew, 2007). Concerning external triggers, it is historical- ly demonstrated that the studied volcanoes did not respond immediately or shortly to dynamic stresses generated by large nearby earthquakes (table I). Moreover, there is no evidence – anec- dotal or otherwise – that either local or remote large earthquakes triggered eruptions in the re- gion (see the NEIC Catalogue available on-line at neic.usgs.gov/neis/epic/ and the INGV Cata- logue available on-line at www.ingv.it); howev- er, also the hypothesis of a stimulus by external earthquakes cannot be fully discounted. For in- stance, the eruptive cycle of 2002-2003 involv- ing eruptions at Etna and Stromboli and de- gassing phenomena at Panarea started about one month after the 6 September 2002, M 5.6, Palermo (fig. 1) earthquake. This sequence of seismic and volcanic phenomena has been in- terpreted as causal by Cigolini et al. (2007). Alternatively, the concurrent eruptions at the Southern Italian volcanoes may have been the effect of the regional tectonic compression (fig. 1b; Goes et al., 2004; Neri et al., 2005). Such a stress may have been periodically re- lieved by a large earthquake on one segment of the regional fault network (Boschi et al., 1997; Neri et al., 2006) or, more often, by swarms of eruptions and moderate-to-small magnitude earthquakes where the triggering threshold is low (i.e., in the active volcanic districts) (e.g., Brodsky et al., 2000). The statistical analysis of earthquakes instrumentally-recorded between 1983 and 2007 (fig. 5) supports this hypothesis although, of course, coupled seismicity in the Etnean and Aeolian areas may alternatively be explained as the consequence of coupled vol- canism triggered by some other cause such as a simultaneous increase of magma supply to Etna and the Aeolian volcanoes. A link between the regional tectonics and the volcanic activity of Etna was previously proposed by Mulargia et al. (1991). Moreover, Feuillet et al. (2006) demonstrated that the largest nearby earth- quakes occurred after years-long-periods of volcanic activity of Etna, this evidence possibly indicating a period of tectonic load that first triggered the volcanic activity and, eventually, a large earthquake. 7. Conclusions Analyses of eruption and earthquake cata- logues show that causal links between concur- rent eruptions at two or three volcanoes among Etna, Stromboli, and Vulcano are plausible, particularly in the Stromboli-Vulcano and Etna- Vulcano cases. These links are also supported by recent and historical anecdotal instances. Limits of statistical results, however, compel further research to better constrain the temporal pattern of such phenomena and to identify their causes. We look forward to our predictions of a moderate incidence of concurrent eruptions be- ing confirmed or refuted with the passage of time and with more sophisticated analyses of new events (e.g., Jaquet and Carniel, 2006). Acknowledgements F. Barberi, M. Bebbington, E. Brodsky, A. Gudmundsson, C. Jaupart, O. Jaquet, D. Pea- cock, and S. Tavani are thanked for useful com- ments and suggestions. L. Da Riva helped with Latin translation from the Historiarum Adver- sus Paganos by Paulus Orosius. Miscellanea 9-03-2009 14:42 Pagina 666 667 Concurrent eruptions at Etna, Stromboli, and Vulcano: casualty or casuality? Table III. Eruption (with VEI ≥ 2) occurrences by month between 0 and 1993 AD at Etna, Stromboli, and Vul- cano. VEI = Volcanic Explosivity Index; 0 = no occurrence; 1 = occurrence. Data are from Simkin and Siebert (1994). year month Etna VEI Stromboli VEI Vulcano eruptions eruptions eruptions 252 2 1 3 0 0 1329 6 1 2 0 0 1329 7 1 3 0 0 1329 8 1 3 0 0 1381 8 1 2 0 0 1408 11 1 3 0 0 1444 2 0 0 1 1536 3 1 3 0 0 1536 4 1 3 0 0 1537 3 1 2 0 0 1537 4 1 2 0 0 1537 5 1 2 0 0 1537 6 1 2 0 0 1537 7 1 2 0 0 1541 7 1 2 0 0 1566 11 1 2 0 0 1603 7 1 2 0 0 1603 8 1 2 0 0 1603 9 1 2 0 0 1603 10 1 2 0 0 1603 11 1 2 0 0 1603 12 1 2 0 0 1604 1 1 2 0 0 1604 2 1 2 0 0 1604 3 1 2 0 0 1604 4 1 2 0 0 1604 5 1 2 0 0 1604 6 1 2 0 0 1604 7 1 2 0 0 1604 8 1 2 0 0 1604 9 1 2 0 0 1604 10 1 2 0 0 1604 11 1 2 0 0 1604 12 1 2 0 0 1605 1 1 2 0 0 1605 2 1 2 0 0 1605 3 1 2 0 0 1605 4 1 2 0 0 Miscellanea 9-03-2009 14:42 Pagina 667 668 A. Billi and R. Funiciello Table III. (continued). year month Etna VEI Stromboli VEI Vulcano eruptions eruptions eruptions 1605 5 1 2 0 0 1605 6 1 2 0 0 1605 7 1 2 0 0 1605 8 1 2 0 0 1605 9 1 2 0 0 1605 10 1 2 0 0 1605 11 1 2 0 0 1605 12 1 2 0 0 1606 1 1 2 0 0 1606 2 1 2 0 0 1606 3 1 2 0 0 1606 4 1 2 0 0 1606 5 1 2 0 0 1606 6 1 2 0 0 1606 7 1 2 0 0 1606 8 1 2 0 0 1606 9 1 2 0 0 1606 10 1 2 0 0 1606 11 1 2 0 0 1606 12 1 2 0 0 1607 1 1 2 0 0 1607 2 1 2 0 0 1607 3 1 2 0 0 1607 4 1 2 0 0 1607 5 1 2 0 0 1607 6 1 2 0 0 1607 7 1 2 0 0 1607 8 1 2 0 0 1607 9 1 2 0 0 1607 10 1 2 0 0 1607 11 1 2 0 0 1607 12 1 2 0 0 1608 1 1 2 0 0 1608 2 1 2 0 0 1608 3 1 2 0 0 1608 4 1 2 0 0 1608 5 1 2 0 0 1608 6 1 2 0 0 1608 7 1 2 0 0 1608 8 1 2 0 0 Miscellanea 9-03-2009 14:42 Pagina 668 669 Concurrent eruptions at Etna, Stromboli, and Vulcano: casualty or casuality? Table III. (continued). year month Etna VEI Stromboli VEI Vulcano eruptions eruptions eruptions 1608 9 1 2 0 0 1608 10 1 2 0 0 1608 11 1 2 0 0 1608 12 1 2 0 0 1609 1 1 2 0 0 1609 2 1 2 0 0 1609 3 1 2 0 0 1609 4 1 2 0 0 1609 5 1 2 0 0 1609 6 1 2 0 0 1609 7 1 2 0 0 1609 8 1 2 0 0 1609 9 1 2 0 0 1609 10 1 2 0 0 1609 11 1 2 0 0 1609 12 1 2 0 0 1610 1 1 2 0 0 1610 2 1 2 0 0 1610 3 1 2 0 0 1610 4 1 2 0 0 1610 5 1 2 0 0 1610 6 1 2 0 0 1610 7 1 2 0 0 1610 8 1 2 0 0 1614 7 1 2 0 0 1614 8 1 2 0 0 1614 9 1 2 0 0 1614 10 1 2 0 0 1614 11 1 2 0 0 1614 12 1 2 0 0 1615 1 1 2 0 0 1615 2 1 2 0 0 1615 3 1 2 0 0 1615 4 1 2 0 0 1615 5 1 2 0 0 1615 6 1 2 0 0 1615 7 1 2 0 0 1615 8 1 2 0 0 1615 9 1 2 0 0 1615 10 1 2 0 0 Miscellanea 9-03-2009 14:42 Pagina 669 670 A. Billi and R. Funiciello Table III. (continued). year month Etna VEI Stromboli VEI Vulcano eruptions eruptions eruptions 1615 11 1 2 0 0 1615 12 1 2 0 0 1616 1 1 2 0 0 1616 2 1 2 0 0 1616 3 1 2 0 0 1616 4 1 2 0 0 1616 5 1 2 0 0 1616 6 1 2 0 0 1616 7 1 2 0 0 1616 8 1 2 0 0 1616 9 1 2 0 0 1616 10 1 2 0 0 1616 11 1 2 0 0 1616 12 1 2 0 0 1617 1 1 2 0 0 1617 2 1 2 0 0 1617 3 1 2 0 0 1617 4 1 2 0 0 1617 5 1 2 0 0 1617 6 1 2 0 0 1617 7 1 2 0 0 1617 8 1 2 0 0 1617 9 1 2 0 0 1617 10 1 2 0 0 1617 11 1 2 0 0 1617 12 1 2 0 0 1618 1 1 2 0 0 1618 2 1 2 0 0 1618 3 1 2 0 0 1618 4 1 2 0 0 1618 5 1 2 0 0 1618 6 1 2 0 0 1618 7 1 2 0 0 1618 8 1 2 0 0 1618 9 1 2 0 0 1618 10 1 2 0 0 1618 11 1 2 0 0 1618 12 1 2 0 0 1619 1 1 2 0 0 1619 2 1 2 0 0 Miscellanea 9-03-2009 14:42 Pagina 670 671 Concurrent eruptions at Etna, Stromboli, and Vulcano: casualty or casuality? Table III. (continued). year month Etna VEI Stromboli VEI Vulcano eruptions eruptions eruptions 1619 3 1 2 0 0 1619 4 1 2 0 0 1619 5 1 2 0 0 1619 6 1 2 0 0 1619 7 1 2 0 0 1619 8 1 2 0 0 1619 9 1 2 0 0 1619 10 1 2 0 0 1619 11 1 2 0 0 1619 12 1 2 0 0 1620 1 1 2 0 0 1620 2 1 2 0 0 1620 3 1 2 0 0 1620 4 1 2 0 0 1620 5 1 2 0 0 1620 6 1 2 0 0 1620 7 1 2 0 0 1620 8 1 2 0 0 1620 9 1 2 0 0 1620 10 1 2 0 0 1620 11 1 2 0 0 1620 12 1 2 0 0 1621 1 1 2 0 0 1621 2 1 2 0 0 1621 3 1 2 0 0 1621 4 1 2 0 0 1621 5 1 2 0 0 1621 6 1 2 0 0 1621 7 1 2 0 0 1621 8 1 2 0 0 1621 9 1 2 0 0 1621 10 1 2 0 0 1621 11 1 2 0 0 1621 12 1 2 0 0 1622 1 1 2 0 0 1622 2 1 2 0 0 1622 3 1 2 0 0 1622 4 1 2 0 0 1622 5 1 2 0 0 1622 6 1 2 0 0 Miscellanea 9-03-2009 14:42 Pagina 671 672 A. Billi and R. Funiciello Table III. (continued). year month Etna VEI Stromboli VEI Vulcano eruptions eruptions eruptions 1622 7 1 2 0 0 1622 8 1 2 0 0 1622 9 1 2 0 0 1622 10 1 2 0 0 1622 11 1 2 0 0 1622 12 1 2 0 0 1623 1 1 2 0 0 1623 2 1 2 0 0 1623 3 1 2 0 0 1623 4 1 2 0 0 1623 5 1 2 0 0 1623 6 1 2 0 0 1623 7 1 2 0 0 1623 8 1 2 0 0 1623 9 1 2 0 0 1623 10 1 2 0 0 1623 11 1 2 0 0 1623 12 1 2 0 0 1624 1 1 2 0 0 1626 3 0 0 1 1626 4 0 0 1 1646 11 1 2 0 0 1646 12 1 2 0 0 1647 1 1 2 0 0 1647 2 1 2 0 0 1647 3 1 2 0 0 1647 4 1 2 0 0 1647 5 1 2 0 0 1647 6 1 2 0 0 1647 7 1 2 0 0 1647 8 1 2 0 0 1647 9 1 2 0 0 1647 10 1 2 0 0 1647 11 1 2 0 0 1669 3 1 3 0 0 1669 4 1 3 0 0 1669 5 1 3 0 0 1669 6 1 3 0 0 1669 7 1 3 0 0 1682 9 1 2 0 0 Miscellanea 9-03-2009 14:42 Pagina 672 673 Concurrent eruptions at Etna, Stromboli, and Vulcano: casualty or casuality? Table III. (continued). year month Etna VEI Stromboli VEI Vulcano eruptions eruptions eruptions 1693 12 1 3 0 0 1694 1 1 3 0 0 1694 2 1 3 0 0 1694 3 1 3 0 0 1694 4 1 3 0 0 1694 5 1 3 0 0 1694 6 1 3 0 0 1694 7 1 3 0 0 1694 8 1 3 0 0 1694 9 1 3 0 0 1694 10 1 3 0 0 1694 11 1 3 0 0 1723 11 1 2 0 0 1723 12 1 2 0 0 1724 1 1 2 0 0 1724 2 1 2 0 0 1724 3 1 2 0 0 1724 4 1 2 0 0 1724 5 1 2 0 0 1731 12 0 0 1 1732 1 0 0 1 1732 2 0 0 1 1732 3 0 0 1 1732 4 0 0 1 1732 5 0 0 1 1732 6 0 0 1 1732 7 0 0 1 1732 8 0 0 1 1732 9 0 0 1 1732 10 0 0 1 1732 11 0 0 1 1732 12 1 2 0 1 1733 1 1 2 0 1 1733 2 0 0 1 1733 3 0 0 1 1733 4 0 0 1 1733 5 0 0 1 1733 6 0 0 1 1733 7 0 0 1 1733 8 0 0 1 Miscellanea 9-03-2009 14:42 Pagina 673 674 A. Billi and R. Funiciello Table III. (continued). year month Etna VEI Stromboli VEI Vulcano eruptions eruptions eruptions 1733 9 0 0 1 1733 10 0 0 1 1733 11 0 0 1 1733 12 0 0 1 1734 1 0 0 1 1734 2 0 0 1 1734 3 0 0 1 1734 4 0 0 1 1734 5 0 0 1 1734 6 0 0 1 1734 7 0 0 1 1734 8 0 0 1 1734 9 0 0 1 1734 10 0 0 1 1734 11 0 0 1 1734 12 0 0 1 1735 1 0 0 1 1735 2 0 0 1 1735 3 0 0 1 1735 4 0 0 1 1735 5 0 0 1 1735 6 0 0 1 1735 7 0 0 1 1735 8 0 0 1 1735 9 0 0 1 1735 10 1 2 0 1 1735 11 1 2 0 1 1735 12 1 2 0 1 1736 1 1 2 0 1 1736 2 1 2 0 1 1736 3 1 2 0 1 1736 4 1 2 0 1 1736 5 1 2 0 1 1736 6 1 2 0 1 1736 7 1 2 0 1 1736 8 1 2 0 1 1736 9 1 2 0 1 1736 10 0 0 1 1736 11 0 0 1 1736 12 0 0 1 Miscellanea 9-03-2009 14:42 Pagina 674 675 Concurrent eruptions at Etna, Stromboli, and Vulcano: casualty or casuality? Table III. (continued). year month Etna VEI Stromboli VEI Vulcano eruptions eruptions eruptions 1737 1 0 0 1 1737 2 0 0 1 1737 3 0 0 1 1737 4 0 0 1 1737 5 0 0 1 1737 6 0 0 1 1737 7 0 0 1 1737 8 0 0 1 1737 9 0 0 1 1737 10 0 0 1 1737 11 0 0 1 1737 12 0 0 1 1738 1 0 0 1 1738 2 0 0 1 1738 3 0 0 1 1738 4 0 0 1 1738 5 0 0 1 1738 6 0 0 1 1738 7 0 0 1 1738 8 0 0 1 1738 9 0 0 1 1738 10 0 0 1 1738 11 0 0 1 1738 12 0 0 1 1739 1 0 0 1 1744 7 1 2 0 0 1744 8 1 2 0 0 1744 9 1 2 0 0 1744 10 1 2 0 0 1744 11 1 2 0 0 1744 12 1 2 0 0 1745 1 1 2 0 0 1745 2 1 2 0 0 1745 3 1 2 0 0 1745 4 1 2 0 0 1745 5 1 2 0 0 1745 6 1 2 0 0 1745 7 1 2 0 0 1745 8 1 2 0 0 1745 9 1 2 0 0 Miscellanea 9-03-2009 14:42 Pagina 675 676 A. Billi and R. Funiciello Table III. (continued). year month Etna VEI Stromboli VEI Vulcano eruptions eruptions eruptions 1747 9 1 2 0 0 1747 10 1 2 0 0 1747 11 1 2 0 0 1747 12 1 2 0 0 1748 1 1 2 0 0 1748 2 1 2 0 0 1748 3 1 2 0 0 1748 4 1 2 0 0 1748 5 1 2 0 0 1748 6 1 2 0 0 1748 7 1 2 0 0 1748 8 1 2 0 0 1748 9 1 2 0 0 1748 10 1 2 0 0 1748 11 1 2 0 0 1748 12 1 2 0 0 1749 1 1 2 0 0 1749 2 1 2 0 0 1749 3 1 2 0 0 1752 12 1 2 0 0 1753 1 1 2 0 0 1753 2 1 2 0 0 1753 3 1 2 0 0 1753 4 1 2 0 0 1753 5 1 2 0 0 1753 6 1 2 0 0 1753 7 1 2 0 0 1753 8 1 2 0 0 1753 9 1 2 0 0 1753 10 1 2 0 0 1753 11 1 2 0 0 1753 12 1 2 0 0 1754 1 1 2 0 0 1754 2 1 2 0 0 1754 3 1 2 0 0 1754 4 1 2 0 0 1754 5 1 2 0 0 1754 6 1 2 0 0 1754 7 1 2 0 0 1754 8 1 2 0 0 Miscellanea 9-03-2009 14:42 Pagina 676 677 Concurrent eruptions at Etna, Stromboli, and Vulcano: casualty or casuality? Table III. (continued). year month Etna VEI Stromboli VEI Vulcano eruptions eruptions eruptions 1754 9 1 2 0 0 1754 10 1 2 0 0 1754 11 1 2 0 0 1754 12 1 2 0 0 1755 1 1 2 0 0 1755 2 1 2 0 0 1755 3 1 2 0 0 1755 4 1 2 0 0 1755 5 1 2 0 0 1755 6 1 2 0 0 1755 7 1 2 0 0 1755 8 1 2 0 0 1755 9 1 2 0 0 1755 10 1 2 0 0 1755 11 1 2 0 0 1755 12 1 2 0 0 1756 1 1 2 0 0 1756 2 1 2 0 0 1756 3 1 2 0 0 1756 4 1 2 0 0 1756 5 1 2 0 0 1756 6 1 2 0 0 1756 7 1 2 0 0 1756 8 1 2 0 0 1756 9 1 2 0 0 1756 10 1 2 0 0 1756 11 1 2 0 0 1756 12 1 2 0 0 1757 1 1 2 0 0 1757 2 1 2 0 0 1757 3 1 2 0 0 1757 4 1 2 0 0 1757 5 1 2 0 0 1757 6 1 2 0 0 1757 7 1 2 0 0 1757 8 1 2 0 0 1757 9 1 2 0 0 1757 10 1 2 0 0 1757 11 1 2 0 0 1757 12 1 2 0 0 Miscellanea 9-03-2009 14:42 Pagina 677 678 A. Billi and R. Funiciello Table III. (continued). year month Etna VEI Stromboli VEI Vulcano eruptions eruptions eruptions 1758 1 1 2 0 0 1758 11 1 2 0 0 1758 12 1 2 0 0 1759 1 1 2 0 0 1759 2 1 2 0 0 1763 2 1 2 0 0 1763 3 1 2 0 0 1763 6 1 3 0 0 1763 7 1 3 0 0 1763 8 1 3 0 0 1763 9 1 3 0 0 1766 4 1 2 0 0 1766 5 1 2 0 0 1766 6 1 2 0 0 1766 7 1 2 0 0 1766 8 1 2 0 0 1766 9 1 2 0 0 1766 10 1 2 0 0 1766 11 1 2 0 0 1771 2 0 0 1 1771 3 0 0 1 1771 4 0 0 1 1771 5 0 0 1 1778 3 0 1 2 0 1780 4 1 2 0 0 1780 5 1 2 0 0 1780 6 1 2 0 0 1781 3 1 2 0 0 1781 4 1 2 0 0 1781 5 1 2 0 0 1787 6 1 4 0 0 1787 7 1 4 0 0 1787 8 1 4 0 0 1791 2 1 2 0 0 1791 3 1 2 0 0 1791 4 1 2 0 0 1791 5 1 2 0 0 1791 6 1 2 0 0 1791 7 1 2 0 0 1791 8 1 2 0 0 Miscellanea 9-03-2009 14:42 Pagina 678 679 Concurrent eruptions at Etna, Stromboli, and Vulcano: casualty or casuality? Table III. (continued). year month Etna VEI Stromboli VEI Vulcano eruptions eruptions eruptions 1791 9 1 2 0 0 1792 3 1 2 0 0 1792 4 1 2 0 0 1792 5 1 3 0 0 1792 6 1 3 0 0 1792 7 1 3 0 0 1792 8 1 3 0 0 1792 9 1 3 0 0 1792 10 1 3 0 0 1792 11 1 3 0 0 1792 12 1 3 0 0 1793 1 1 3 0 0 1793 2 1 3 0 0 1793 3 1 3 0 0 1793 4 1 3 0 0 1793 5 1 3 0 0 1797 12 1 2 0 0 1798 1 1 2 0 0 1798 2 1 2 0 0 1798 3 1 2 0 0 1798 4 1 2 0 0 1798 5 1 2 0 0 1798 6 1 2 0 0 1798 7 1 2 0 0 1798 8 1 2 0 0 1798 9 1 2 0 0 1798 10 1 2 0 0 1798 11 1 2 0 0 1798 12 1 2 0 0 1799 1 1 2 0 0 1799 2 1 2 0 0 1799 3 1 2 0 0 1799 4 1 2 0 0 1799 5 1 2 0 0 1799 6 1 2 0 0 1799 7 1 2 0 0 1799 8 1 2 0 0 1799 9 1 2 0 0 1799 10 1 2 0 0 1799 11 1 2 0 0 Miscellanea 9-03-2009 14:42 Pagina 679 680 A. Billi and R. Funiciello Table III. (continued). year month Etna VEI Stromboli VEI Vulcano eruptions eruptions eruptions 1799 12 1 2 0 0 1800 1 1 2 0 0 1800 2 1 2 0 0 1800 3 1 2 0 0 1800 4 1 2 0 0 1800 5 1 2 0 0 1800 6 1 2 0 0 1800 7 1 2 0 0 1800 8 1 2 0 0 1800 9 1 2 0 0 1800 10 1 2 0 0 1800 11 1 2 0 0 1800 12 1 2 0 0 1801 1 1 2 0 0 1802 11 1 2 0 0 1803 12 1 2 0 0 1804 1 1 2 0 0 1804 2 1 2 0 0 1804 3 1 2 0 0 1804 4 1 2 0 0 1804 5 1 2 0 0 1804 6 1 2 0 0 1804 7 1 2 0 0 1804 8 1 2 0 0 1804 9 1 2 0 0 1804 10 1 2 0 0 1804 11 1 2 0 0 1804 12 1 2 0 0 1805 1 1 2 0 0 1805 2 1 2 0 0 1805 3 1 2 0 0 1805 4 1 2 0 0 1805 5 1 2 0 0 1805 6 1 2 0 0 1805 7 1 2 0 0 1805 8 1 2 0 0 1805 9 1 2 0 0 1805 10 1 2 0 0 1805 11 1 2 0 0 1805 12 1 2 0 0 Miscellanea 9-03-2009 14:42 Pagina 680 681 Concurrent eruptions at Etna, Stromboli, and Vulcano: casualty or casuality? Table III. (continued). year month Etna VEI Stromboli VEI Vulcano eruptions eruptions eruptions 1806 1 1 2 0 0 1806 2 1 2 0 0 1806 3 1 2 0 0 1806 4 1 2 0 0 1806 5 1 2 0 0 1806 6 1 2 0 0 1806 7 1 2 0 0 1806 8 1 2 0 0 1806 9 1 2 0 0 1806 10 1 2 0 0 1806 11 1 2 0 0 1806 12 1 2 0 0 1807 1 1 2 0 0 1807 2 1 2 0 0 1807 3 1 2 0 0 1807 4 1 2 0 0 1807 5 1 2 0 0 1807 6 1 2 0 0 1807 7 1 2 0 0 1807 8 1 2 0 0 1807 9 1 2 0 0 1807 10 1 2 0 0 1807 11 1 2 0 0 1807 12 1 2 0 0 1808 1 1 2 0 0 1808 2 1 2 0 0 1808 3 1 2 0 0 1808 4 1 2 0 0 1808 5 1 2 0 0 1808 6 1 2 0 0 1808 7 1 2 0 0 1808 8 1 2 0 0 1808 9 1 2 0 0 1808 10 1 2 0 0 1808 11 1 2 0 0 1808 12 1 2 0 0 1809 1 1 2 0 0 1809 2 1 2 0 0 1809 3 1 2 0 0 1809 4 1 2 0 0 Miscellanea 9-03-2009 14:42 Pagina 681 682 A. Billi and R. Funiciello Table III. (continued). year month Etna VEI Stromboli VEI Vulcano eruptions eruptions eruptions 1809 5 1 2 0 0 1809 6 1 2 0 0 1809 7 1 2 0 0 1809 8 1 2 0 0 1809 9 1 2 0 0 1809 10 1 2 0 0 1809 11 1 2 0 0 1811 10 1 2 0 0 1811 11 1 2 0 0 1811 12 1 2 0 0 1812 1 1 2 0 0 1812 2 1 2 0 0 1812 3 1 2 0 0 1812 4 1 2 0 0 1812 5 1 2 0 0 1819 5 1 3 0 0 1819 6 1 3 0 0 1819 7 1 3 0 0 1819 8 1 3 0 0 1822 10 0 1 3 0 1828 8 1 2 0 0 1828 9 1 2 0 0 1828 10 1 2 0 0 1828 11 1 2 0 0 1828 12 1 2 0 0 1829 1 1 2 0 0 1829 2 1 2 0 0 1829 3 1 2 0 0 1829 4 1 2 0 0 1829 5 1 2 0 0 1829 6 1 2 0 0 1829 7 1 2 0 0 1829 8 1 2 0 0 1829 9 1 2 0 0 1829 10 1 2 0 0 1829 11 1 2 0 0 1829 12 1 2 0 0 1830 1 1 2 0 0 1830 2 1 2 0 0 1830 3 1 2 0 0 Miscellanea 9-03-2009 14:42 Pagina 682 683 Concurrent eruptions at Etna, Stromboli, and Vulcano: casualty or casuality? Table III. (continued). year month Etna VEI Stromboli VEI Vulcano eruptions eruptions eruptions 1830 4 1 2 0 0 1830 5 1 2 0 0 1830 6 1 2 0 0 1830 7 1 2 0 0 1830 8 1 2 0 0 1830 9 1 2 0 0 1830 10 1 2 0 0 1830 11 1 2 0 0 1830 12 1 2 0 0 1831 1 1 2 0 0 1831 2 1 2 0 0 1831 3 1 2 0 0 1831 4 1 2 0 0 1831 5 1 2 0 0 1831 6 1 2 0 0 1831 7 1 2 0 0 1831 8 1 2 0 0 1831 9 1 2 0 0 1831 10 1 2 0 0 1831 11 1 2 0 0 1831 12 1 2 0 0 1832 1 1 2 0 0 1832 2 1 2 0 0 1832 3 1 2 0 0 1832 4 1 2 0 0 1832 5 1 2 0 0 1832 6 1 2 0 0 1832 7 1 2 0 0 1832 8 1 2 0 0 1832 9 1 2 0 0 1832 10 1 2 0 0 1832 11 1 2 0 0 1833 3 1 2 0 0 1838 7 1 2 0 0 1838 8 1 2 0 0 1838 9 1 2 0 0 1838 10 1 2 0 0 1838 11 1 2 0 0 1838 12 1 2 0 0 1839 1 1 2 0 0 Miscellanea 9-03-2009 14:42 Pagina 683 684 A. Billi and R. Funiciello Table III. (continued). year month Etna VEI Stromboli VEI Vulcano eruptions eruptions eruptions 1839 2 1 2 0 0 1842 11 1 2 0 0 1842 12 1 2 0 0 1843 11 1 2 0 0 1852 8 1 2 0 0 1852 9 1 2 0 0 1852 10 1 2 0 0 1852 11 1 2 0 0 1852 12 1 2 0 0 1853 1 1 2 0 0 1853 2 1 2 0 0 1853 3 1 2 0 0 1853 4 1 2 0 0 1853 5 1 2 0 0 1855 10 0 1 2 0 1856 7 0 1 2 0 1863 5 1 2 0 0 1863 6 1 2 0 0 1863 7 1 2 0 0 1864 8 1 2 0 0 1864 9 1 2 0 0 1865 1 1 2 1 2 0 1865 2 1 2 1 2 0 1865 3 1 2 0 0 1865 4 1 2 0 0 1865 5 1 2 0 0 1865 6 1 2 0 0 1868 11 1 3 0 0 1868 12 1 3 0 0 1873 9 0 0 1 1873 10 0 0 1 1873 11 0 0 1 1873 12 0 0 1 1874 1 0 0 1 1874 2 0 0 1 1874 3 0 0 1 1874 4 0 0 1 1874 5 1 2 0 1 1874 6 1 2 1 2 1 1874 7 1 2 0 1 Miscellanea 9-03-2009 14:42 Pagina 684 685 Concurrent eruptions at Etna, Stromboli, and Vulcano: casualty or casuality? Table III. (continued). year month Etna VEI Stromboli VEI Vulcano eruptions eruptions eruptions 1874 8 1 2 0 1 1874 9 0 0 1 1874 10 0 0 1 1874 11 0 0 1 1874 12 1 2 0 1 1875 1 1 2 0 1 1875 2 1 2 0 1 1875 3 1 2 0 1 1875 4 1 2 0 1 1875 5 1 2 0 1 1875 6 1 2 0 1 1875 7 1 2 0 1 1875 8 1 2 0 1 1875 9 1 2 0 1 1875 10 1 2 0 1 1875 11 1 2 0 1 1875 12 1 2 0 1 1876 1 1 2 0 1 1876 2 1 2 0 1 1876 3 1 2 0 1 1876 4 1 2 0 1 1876 5 1 2 0 1 1876 6 1 2 0 1 1876 7 1 2 0 1 1876 8 1 2 0 1 1876 9 1 2 0 1 1876 10 1 2 0 1 1876 11 1 2 0 1 1876 12 1 2 0 1 1877 1 1 2 0 1 1877 2 1 2 0 1 1877 3 1 2 0 1 1877 4 1 2 0 1 1877 5 1 2 0 1 1877 6 1 2 0 1 1877 7 1 2 0 1 1877 8 1 2 0 1 1877 9 1 2 0 1 1877 10 1 2 0 1 1877 11 1 2 0 1 Miscellanea 9-03-2009 14:42 Pagina 685 686 A. Billi and R. Funiciello Table III. (continued). year month Etna VEI Stromboli VEI Vulcano eruptions eruptions eruptions 1877 12 1 2 0 1 1878 1 1 2 0 1 1878 2 1 2 0 1 1878 3 1 2 0 1 1878 4 1 2 0 1 1878 5 1 2 0 1 1878 6 1 2 0 1 1878 7 1 2 0 1 1878 8 1 2 0 1 1878 9 1 2 0 1 1878 10 1 2 0 1 1878 11 1 2 0 1 1878 12 1 2 0 1 1879 1 1 2 0 1 1879 2 1 2 1 2 0 1879 3 1 2 0 0 1879 4 1 2 0 0 1879 5 1 3 0 0 1879 6 1 3 1 2 0 1879 7 1 2 0 0 1879 8 1 2 0 0 1879 9 1 2 0 0 1879 10 1 2 0 0 1879 11 1 2 0 0 1879 12 1 2 0 0 1880 1 1 2 0 0 1880 2 1 2 0 0 1880 3 1 2 0 0 1880 4 1 2 0 0 1880 5 1 2 0 0 1880 6 1 2 0 0 1880 7 1 2 0 0 1880 8 1 2 0 0 1880 9 1 2 0 0 1880 10 1 2 0 0 1880 11 1 2 0 0 1880 12 1 2 0 0 1881 1 1 2 0 0 1881 2 1 2 0 0 1881 3 1 2 0 0 Miscellanea 9-03-2009 14:42 Pagina 686 687 Concurrent eruptions at Etna, Stromboli, and Vulcano: casualty or casuality? Table III. (continued). year month Etna VEI Stromboli VEI Vulcano eruptions eruptions eruptions 1881 4 1 2 0 0 1881 5 1 2 0 0 1881 6 1 2 0 0 1881 7 1 2 0 0 1881 8 1 2 0 0 1881 9 1 2 0 0 1881 10 1 2 1 2 0 1881 11 1 2 0 0 1881 12 1 2 0 0 1882 1 1 2 0 0 1882 2 1 2 0 0 1882 3 1 2 0 0 1882 4 1 2 0 0 1882 5 1 2 0 0 1882 6 1 2 0 0 1882 7 1 2 0 0 1882 8 1 2 0 0 1882 9 1 2 0 0 1882 10 1 2 0 0 1882 11 1 2 1 3 0 1882 12 1 2 0 0 1883 1 1 2 0 0 1883 2 1 2 0 0 1883 3 1 2 0 0 1885 3 0 1 3 0 1886 1 0 0 1 1886 5 1 3 0 0 1886 6 1 3 0 0 1888 8 0 0 1 1888 9 0 0 1 1888 10 0 1 2 1 1888 11 0 1 2 1 1888 12 0 1 2 1 1889 1 0 1 2 1 1889 2 0 1 2 1 1889 3 0 1 2 1 1889 4 0 1 2 1 1889 5 0 1 2 1 1889 6 0 1 2 1 1889 7 0 0 1 Miscellanea 9-03-2009 14:42 Pagina 687 688 A. Billi and R. Funiciello Table III. (continued). year month Etna VEI Stromboli VEI Vulcano eruptions eruptions eruptions 1889 8 0 0 1 1889 9 0 0 1 1889 10 0 0 1 1889 11 0 0 1 1889 12 0 0 1 1890 1 0 0 1 1890 2 0 0 1 1890 3 0 0 1 1891 6 0 1 3 0 1891 7 0 1 3 0 1891 8 0 1 3 0 1892 7 1 2 0 0 1892 8 1 2 0 0 1892 9 1 2 0 0 1892 10 1 2 0 0 1892 11 1 2 1 2 0 1892 12 1 2 0 0 1893 1 0 1 2 0 1893 4 1 2 0 0 1893 5 1 2 0 0 1893 6 1 2 0 0 1893 7 1 2 0 0 1893 8 1 2 0 0 1893 9 1 2 0 0 1893 10 1 2 0 0 1893 11 1 2 1 2 0 1893 12 1 2 0 0 1894 1 1 2 0 0 1894 2 1 2 0 0 1894 3 1 2 0 0 1894 4 1 2 0 0 1894 5 1 2 0 0 1894 6 1 2 0 0 1894 7 1 2 0 0 1894 8 1 2 0 0 1894 9 1 2 0 0 1894 10 1 2 0 0 1894 11 1 2 0 0 1894 12 1 2 0 0 1895 1 1 2 0 0 Miscellanea 9-03-2009 14:42 Pagina 688 689 Concurrent eruptions at Etna, Stromboli, and Vulcano: casualty or casuality? Table III. (continued). year month Etna VEI Stromboli VEI Vulcano eruptions eruptions eruptions 1895 2 1 2 0 0 1895 3 1 2 1 2 0 1895 4 1 2 0 0 1895 5 1 2 0 0 1895 6 1 2 0 0 1895 7 1 2 0 0 1895 8 1 2 0 0 1895 9 1 2 0 0 1895 10 1 2 0 0 1895 11 1 2 0 0 1895 12 1 2 0 0 1896 1 1 2 0 0 1896 2 1 2 0 0 1896 3 1 2 0 0 1896 4 1 2 0 0 1896 5 1 2 0 0 1896 6 1 2 0 0 1896 7 1 2 1 2 0 1896 8 1 2 0 0 1896 9 1 2 0 0 1896 10 1 2 0 0 1896 11 1 2 0 0 1896 12 1 2 0 0 1897 1 1 2 0 0 1897 2 1 2 0 0 1897 3 1 2 0 0 1897 4 1 2 0 0 1897 5 1 2 0 0 1897 6 1 2 0 0 1897 7 1 2 1 2 0 1897 8 1 2 0 0 1897 9 1 2 0 0 1897 10 1 2 0 0 1897 11 1 2 0 0 1897 12 1 2 0 0 1898 1 1 2 0 0 1898 2 1 2 0 0 1898 3 1 2 0 0 1898 4 1 2 0 0 1898 5 1 2 0 0 Miscellanea 9-03-2009 14:42 Pagina 689 690 A. Billi and R. Funiciello Table III. (continued). year month Etna VEI Stromboli VEI Vulcano eruptions eruptions eruptions 1898 6 1 2 0 0 1898 8 0 1 2 0 1899 7 1 3 0 0 1899 8 1 3 0 0 1900 8 0 1 2 0 1900 10 0 1 2 0 1903 1 0 1 2 0 1903 2 0 1 2 0 1903 3 0 1 2 0 1903 4 0 1 2 0 1903 5 0 1 2 0 1903 6 0 1 2 0 1903 11 0 1 2 0 1905 4 0 1 2 0 1906 4 0 1 2 0 1906 7 0 1 2 0 1907 1 0 1 3 0 1907 2 0 1 3 0 1907 3 0 1 3 0 1907 4 0 1 3 0 1907 5 0 1 3 0 1908 4 1 2 0 0 1910 3 1 2 0 0 1910 4 1 2 0 0 1910 12 1 2 0 0 1911 1 1 2 0 0 1911 2 1 2 0 0 1912 7 0 1 2 0 1912 8 1 3 1 2 0 1913 11 1 2 0 0 1913 12 1 2 0 0 1914 1 1 2 0 0 1914 2 1 2 0 0 1914 3 1 2 0 0 1914 4 1 2 0 0 1914 5 1 2 0 0 1914 6 1 2 0 0 1914 7 1 2 0 0 1914 8 1 2 0 0 1914 9 1 2 0 0 Miscellanea 9-03-2009 14:42 Pagina 690 691 Concurrent eruptions at Etna, Stromboli, and Vulcano: casualty or casuality? Table III. (continued). year month Etna VEI Stromboli VEI Vulcano eruptions eruptions eruptions 1914 10 1 2 0 0 1914 11 1 2 0 0 1914 12 1 2 0 0 1915 1 1 2 0 0 1915 2 1 2 0 0 1915 3 1 2 0 0 1915 4 1 2 0 0 1915 5 1 2 0 0 1915 6 1 2 1 2 0 1915 7 1 2 1 2 0 1915 8 1 2 1 2 0 1915 9 1 2 1 2 0 1915 10 1 2 1 2 0 1915 11 1 2 1 2 0 1915 12 1 2 0 0 1916 1 1 2 0 0 1916 2 1 2 0 0 1916 3 1 2 0 0 1916 4 1 2 0 0 1916 5 1 2 0 0 1916 6 1 2 1 2 0 1916 7 1 2 1 2 0 1916 8 1 2 0 0 1916 9 1 2 0 0 1916 10 1 2 0 0 1916 11 1 2 0 0 1916 12 1 2 0 0 1917 1 1 2 0 0 1917 2 1 2 0 0 1917 3 1 2 0 0 1917 6 1 2 0 0 1917 7 1 2 0 0 1919 3 1 2 0 0 1919 4 1 2 0 0 1919 5 1 2 1 3 0 1919 6 1 2 0 0 1919 7 1 2 0 0 1919 8 1 2 0 0 1919 9 1 2 0 0 1919 10 1 2 0 0 Miscellanea 9-03-2009 14:42 Pagina 691 692 A. Billi and R. Funiciello Table III. (continued). year month Etna VEI Stromboli VEI Vulcano eruptions eruptions eruptions 1919 11 1 2 0 0 1919 12 1 2 0 0 1920 1 1 2 0 0 1920 2 1 2 0 0 1920 3 1 2 0 0 1920 4 1 2 0 0 1920 5 1 2 0 0 1920 6 1 2 0 0 1920 7 1 2 0 0 1920 8 1 2 0 0 1920 9 1 2 0 0 1920 10 1 2 0 0 1920 11 1 2 0 0 1920 12 1 2 0 0 1921 1 1 2 0 0 1921 2 1 2 0 0 1921 3 1 2 0 0 1921 4 1 2 0 0 1921 5 1 2 0 0 1921 6 1 2 1 2 0 1921 7 1 2 0 0 1921 8 1 2 0 0 1921 9 1 2 0 0 1921 10 1 2 0 0 1921 11 1 2 0 0 1921 12 1 2 0 0 1922 1 1 2 0 0 1922 2 1 2 0 0 1922 3 1 2 0 0 1922 4 1 2 0 0 1922 5 1 2 0 0 1922 6 1 2 0 0 1922 7 1 2 0 0 1922 8 1 2 0 0 1922 9 1 2 0 0 1922 10 1 2 0 0 1922 11 1 2 0 0 1922 12 1 2 0 0 1923 1 1 2 0 0 1923 2 1 2 0 0 Miscellanea 9-03-2009 14:42 Pagina 692 693 Concurrent eruptions at Etna, Stromboli, and Vulcano: casualty or casuality? Table III. (continued). year month Etna VEI Stromboli VEI Vulcano eruptions eruptions eruptions 1923 3 1 2 0 0 1923 4 1 2 0 0 1923 5 1 2 0 0 1923 6 1 2 0 0 1923 7 1 2 0 0 1930 2 0 1 2 0 1930 9 0 1 3 0 1930 10 0 1 3 0 1930 11 0 1 3 0 1930 12 0 1 3 0 1931 7 1 2 0 0 1931 8 1 2 0 0 1931 9 1 2 0 0 1931 10 1 2 0 0 1931 11 1 2 0 0 1931 12 1 2 0 0 1932 1 1 2 0 0 1932 2 1 2 0 0 1932 3 1 2 0 0 1932 4 1 2 0 0 1932 5 1 2 0 0 1932 6 1 2 0 0 1932 7 1 2 0 0 1932 8 1 2 0 0 1932 9 1 2 0 0 1932 10 1 2 0 0 1932 11 1 2 0 0 1932 12 1 2 0 0 1933 1 1 2 0 0 1933 2 1 2 0 0 1933 3 1 2 0 0 1933 4 1 2 0 0 1933 5 1 2 0 0 1933 6 1 2 0 0 1933 7 1 2 0 0 1933 8 1 2 0 0 1933 9 1 2 0 0 1934 2 0 1 2 0 1934 8 0 1 2 0 1935 7 1 2 0 0 Miscellanea 9-03-2009 14:42 Pagina 693 694 A. Billi and R. Funiciello Table III. (continued). year month Etna VEI Stromboli VEI Vulcano eruptions eruptions eruptions 1935 8 1 2 0 0 1935 9 1 2 0 0 1935 10 1 2 0 0 1935 11 1 2 0 0 1935 12 1 2 0 0 1936 1 1 2 1 2 0 1936 2 1 2 0 0 1936 3 1 2 0 0 1936 4 1 2 0 0 1936 5 1 2 0 0 1936 6 1 2 0 0 1936 7 1 2 0 0 1936 8 1 2 0 0 1936 9 1 2 0 0 1936 10 1 2 0 0 1936 11 1 2 0 0 1936 12 1 2 0 0 1937 1 1 2 1 2 0 1937 2 1 2 0 0 1937 3 1 2 0 0 1937 4 1 2 0 0 1937 5 1 2 0 0 1937 6 1 2 0 0 1937 7 1 2 0 0 1937 8 1 2 0 0 1937 9 1 2 0 0 1937 10 1 2 0 0 1937 11 1 2 1 2 0 1937 12 1 2 0 0 1938 1 1 2 0 0 1938 2 1 2 0 0 1938 3 1 2 0 0 1938 4 1 2 0 0 1938 5 1 2 0 0 1938 6 1 2 0 0 1938 7 1 2 0 0 1938 8 1 2 0 0 1938 9 1 2 0 0 1938 10 1 2 0 0 1938 11 1 2 1 2 0 Miscellanea 9-03-2009 14:42 Pagina 694 695 Concurrent eruptions at Etna, Stromboli, and Vulcano: casualty or casuality? Table III. (continued). year month Etna VEI Stromboli VEI Vulcano eruptions eruptions eruptions 1938 12 1 2 1 2 0 1939 1 1 2 1 2 0 1939 2 1 2 1 2 0 1939 3 1 2 1 2 0 1939 4 1 2 1 2 0 1939 5 1 2 1 2 0 1939 6 1 2 1 2 0 1939 7 1 2 0 0 1939 8 1 2 0 0 1939 9 1 2 0 0 1939 10 1 2 0 0 1939 11 1 2 0 0 1939 12 1 2 0 0 1940 3 1 3 0 0 1940 4 1 3 0 0 1940 5 1 3 0 0 1940 6 1 3 0 0 1940 7 1 3 0 0 1940 8 1 3 0 0 1940 9 1 3 0 0 1940 10 1 3 0 0 1940 11 1 3 0 0 1940 12 1 3 0 0 1941 1 1 3 0 0 1941 2 1 3 0 0 1941 3 1 3 0 0 1941 4 1 3 0 0 1941 5 1 3 0 0 1941 6 1 3 0 0 1941 7 1 3 0 0 1941 8 1 3 1 2 0 1941 9 1 3 0 0 1941 10 1 3 0 0 1941 11 1 3 0 0 1941 12 1 3 0 0 1942 1 1 3 0 0 1942 2 1 3 0 0 1942 3 1 3 0 0 1942 4 1 3 0 0 1942 5 1 3 0 0 Miscellanea 9-03-2009 14:42 Pagina 695 696 A. Billi and R. Funiciello Table III. (continued). year month Etna VEI Stromboli VEI Vulcano eruptions eruptions eruptions 1942 6 1 3 0 0 1942 7 1 2 0 0 1943 12 0 1 2 0 1944 1 0 1 2 0 1944 2 0 1 2 0 1944 8 0 1 2 0 1944 9 0 1 2 0 1944 10 0 1 2 0 1947 1 1 2 0 0 1947 2 1 2 0 0 1949 6 0 1 2 0 1949 12 1 2 0 0 1950 1 1 2 0 0 1950 10 0 1 2 0 1950 11 1 2 0 0 1950 12 1 2 0 0 1951 1 1 2 0 0 1951 2 1 2 0 0 1951 3 1 2 0 0 1951 4 1 2 1 2 0 1951 5 1 2 0 0 1951 6 1 2 0 0 1951 7 1 2 0 0 1951 8 1 2 0 0 1951 9 1 2 0 0 1951 10 1 2 0 0 1951 11 1 2 0 0 1951 12 1 2 0 0 1952 6 0 1 2 0 1953 7 1 2 0 0 1954 2 0 1 2 0 1954 3 0 1 2 0 1954 12 0 1 2 0 1955 1 0 1 2 0 1955 2 0 1 2 0 1955 3 0 1 2 0 1955 4 1 2 1 2 0 1955 5 1 2 1 2 0 1955 6 1 2 0 0 1955 7 1 2 0 0 Miscellanea 9-03-2009 14:42 Pagina 696 697 Concurrent eruptions at Etna, Stromboli, and Vulcano: casualty or casuality? Table III. (continued). year month Etna VEI Stromboli VEI Vulcano eruptions eruptions eruptions 1955 8 1 2 0 0 1955 9 1 2 0 0 1955 10 1 2 0 0 1955 11 1 2 0 0 1955 12 1 2 0 0 1956 1 1 2 0 0 1956 2 1 2 0 0 1956 3 1 2 0 0 1956 4 1 2 0 0 1957 2 1 2 0 0 1957 3 1 2 0 0 1957 4 1 2 0 0 1957 5 1 2 0 0 1957 8 1 2 0 0 1957 9 1 2 0 0 1957 10 1 2 0 0 1957 11 1 2 0 0 1957 12 1 2 0 0 1958 1 1 2 0 0 1958 2 1 2 0 0 1958 3 1 2 0 0 1958 4 1 2 0 0 1958 5 1 2 0 0 1959 5 0 1 2 0 1959 10 1 3 0 0 1959 11 1 3 0 0 1959 12 1 3 0 0 1960 1 1 3 0 0 1960 2 1 3 0 0 1960 3 1 3 0 0 1960 4 1 3 0 0 1960 5 1 3 0 0 1960 6 1 3 0 0 1960 7 1 3 0 0 1960 8 1 3 0 0 1960 9 1 3 0 0 1960 10 1 3 0 0 1960 11 1 3 0 0 1960 12 1 3 0 0 1961 1 1 3 0 0 Miscellanea 9-03-2009 14:42 Pagina 697 698 A. Billi and R. Funiciello Table III. (continued). year month Etna VEI Stromboli VEI Vulcano eruptions eruptions eruptions 1961 2 1 3 0 0 1961 3 1 3 0 0 1961 4 1 3 0 0 1961 5 1 3 0 0 1961 6 1 3 0 0 1961 7 1 3 0 0 1961 8 1 3 0 0 1961 9 1 3 0 0 1961 10 1 3 0 0 1961 11 1 3 0 0 1961 12 1 3 0 0 1962 1 1 3 0 0 1962 2 1 3 0 0 1962 3 1 3 0 0 1962 4 1 3 0 0 1962 5 1 3 0 0 1962 6 1 3 0 0 1962 7 1 3 0 0 1962 8 1 3 0 0 1962 9 1 3 0 0 1962 10 1 3 0 0 1962 11 1 3 0 0 1962 12 1 3 0 0 1963 1 1 3 0 0 1963 2 1 3 0 0 1963 3 1 3 0 0 1963 4 1 3 0 0 1963 5 1 3 0 0 1963 6 1 3 0 0 1963 7 1 3 0 0 1963 8 1 3 0 0 1963 9 1 3 0 0 1963 10 1 3 0 0 1963 11 1 3 0 0 1963 12 1 3 0 0 1964 1 1 3 0 0 1964 2 1 3 0 0 1964 3 1 3 0 0 1964 4 1 3 0 0 1964 5 1 3 0 0 Miscellanea 9-03-2009 14:42 Pagina 698 699 Concurrent eruptions at Etna, Stromboli, and Vulcano: casualty or casuality? Table III. (continued). year month Etna VEI Stromboli VEI Vulcano eruptions eruptions eruptions 1964 6 1 3 0 0 1964 7 1 3 0 0 1964 8 1 3 0 0 1964 9 1 3 0 0 1964 10 1 3 0 0 1964 11 1 3 0 0 1964 12 1 3 0 0 1966 1 1 2 0 0 1966 2 1 2 0 0 1966 3 1 2 0 0 1966 4 1 2 1 2 0 1966 5 1 2 0 0 1966 6 1 2 0 0 1966 7 1 2 0 0 1966 8 1 2 0 0 1966 9 1 2 0 0 1966 10 1 2 0 0 1966 11 1 2 0 0 1966 12 1 2 0 0 1967 1 1 2 0 0 1967 2 1 2 0 0 1967 3 1 2 0 0 1967 4 1 2 0 0 1967 5 1 2 0 0 1967 6 1 2 0 0 1967 7 1 2 0 0 1967 8 1 2 0 0 1967 9 1 2 0 0 1967 10 1 2 0 0 1967 11 1 2 0 0 1967 12 1 2 0 0 1968 1 1 2 0 0 1968 2 1 2 0 0 1968 3 1 2 0 0 1968 4 1 2 0 0 1968 5 1 2 0 0 1968 6 1 2 0 0 1968 7 1 2 0 0 1968 8 1 2 0 0 1968 9 1 2 0 0 Miscellanea 9-03-2009 14:42 Pagina 699 700 A. Billi and R. Funiciello Table III. (continued). year month Etna VEI Stromboli VEI Vulcano eruptions eruptions eruptions 1968 10 1 2 0 0 1968 11 1 2 0 0 1968 12 1 2 0 0 1969 1 1 2 0 0 1969 2 1 2 0 0 1969 3 1 2 0 0 1969 4 1 2 0 0 1969 5 1 2 0 0 1969 6 1 2 0 0 1969 7 1 2 0 0 1969 8 1 2 0 0 1969 9 1 2 0 0 1969 10 1 2 0 0 1969 11 1 2 0 0 1969 12 1 2 0 0 1970 1 1 2 0 0 1970 2 1 2 0 0 1970 3 1 2 0 0 1970 4 1 2 0 0 1970 5 1 2 0 0 1970 6 1 2 0 0 1970 7 1 2 0 0 1970 8 1 2 0 0 1970 9 1 2 0 0 1970 10 1 2 0 0 1970 11 1 2 0 0 1970 12 1 2 0 0 1971 1 1 2 0 0 1971 3 0 1 2 0 1971 4 1 2 1 2 0 1971 5 1 2 1 2 0 1971 6 1 2 0 0 1971 9 1 2 0 0 1971 10 1 2 0 0 1971 11 1 2 0 0 1971 12 1 2 0 0 1972 1 1 2 0 0 1972 2 1 2 0 0 1972 3 1 2 0 0 1972 4 1 2 0 0 Miscellanea 9-03-2009 14:42 Pagina 700 701 Concurrent eruptions at Etna, Stromboli, and Vulcano: casualty or casuality? Table III. (continued). year month Etna VEI Stromboli VEI Vulcano eruptions eruptions eruptions 1972 5 1 2 0 0 1972 6 1 2 0 0 1972 7 1 2 0 0 1972 8 1 2 0 0 1972 9 1 2 0 0 1972 10 1 2 0 0 1972 11 1 2 0 0 1972 12 1 2 0 0 1973 1 1 2 0 0 1973 2 1 2 0 0 1973 3 1 2 0 0 1973 4 1 2 0 0 1973 5 1 2 0 0 1973 6 1 2 0 0 1973 7 1 2 0 0 1973 8 1 2 0 0 1973 9 1 2 0 0 1973 10 1 2 0 0 1973 11 1 2 0 0 1973 12 1 2 0 0 1974 1 1 2 0 0 1974 2 1 2 0 0 1974 3 1 2 0 0 1974 4 1 2 0 0 1974 5 1 2 0 0 1974 6 1 2 0 0 1974 7 1 2 0 0 1974 8 1 2 0 0 1974 9 1 2 0 0 1974 10 1 2 0 0 1974 11 1 2 0 0 1974 12 1 2 0 0 1975 1 1 2 0 0 1975 2 1 2 0 0 1975 3 1 2 0 0 1975 4 1 2 0 0 1975 5 1 2 0 0 1975 6 1 2 0 0 1975 7 1 2 0 0 1975 8 1 2 0 0 Miscellanea 9-03-2009 14:42 Pagina 701 702 A. Billi and R. Funiciello Table III. (continued). year month Etna VEI Stromboli VEI Vulcano eruptions eruptions eruptions 1975 9 1 2 0 0 1975 10 1 2 0 0 1975 11 1 2 0 0 1975 12 1 2 0 0 1976 1 1 2 0 0 1976 2 1 2 0 0 1976 3 1 2 0 0 1976 4 1 2 0 0 1976 5 1 2 0 0 1976 6 1 2 0 0 1976 7 1 2 0 0 1976 8 1 2 0 0 1976 9 1 2 0 0 1976 10 1 2 0 0 1976 11 1 2 0 0 1976 12 1 2 0 0 1977 1 1 2 0 0 1977 2 1 2 0 0 1977 3 1 2 0 0 1977 4 1 2 0 0 1977 5 1 2 0 0 1977 6 1 2 0 0 1977 7 1 2 0 0 1977 8 1 2 0 0 1977 9 1 2 0 0 1977 10 1 2 0 0 1977 11 1 2 0 0 1977 12 1 2 0 0 1978 1 1 2 0 0 1978 2 1 2 0 0 1978 3 1 2 0 0 1978 4 1 2 0 0 1978 5 1 2 0 0 1978 6 1 2 0 0 1978 7 1 2 0 0 1978 8 1 2 0 0 1978 9 1 2 0 0 1978 10 1 2 0 0 1978 11 1 2 0 0 1978 12 1 2 0 0 Miscellanea 9-03-2009 14:42 Pagina 702 703 Concurrent eruptions at Etna, Stromboli, and Vulcano: casualty or casuality? Table III. (continued). year month Etna VEI Stromboli VEI Vulcano eruptions eruptions eruptions 1979 1 1 2 0 0 1979 2 1 2 0 0 1979 3 1 2 0 0 1979 7 1 2 0 0 1979 8 1 2 0 0 1979 9 1 2 0 0 1979 10 1 2 0 0 1979 11 1 2 0 0 1979 12 1 2 0 0 1980 1 1 2 0 0 1980 2 1 2 0 0 1980 3 1 2 0 0 1980 4 1 2 0 0 1980 5 1 2 0 0 1980 6 1 2 0 0 1980 7 1 3 0 0 1980 8 1 3 0 0 1980 9 1 3 0 0 1980 10 1 2 0 0 1980 11 1 2 0 0 1980 12 1 2 0 0 1981 1 1 2 0 0 1981 2 1 2 0 0 1981 3 1 2 0 0 1981 4 1 2 0 0 1981 5 1 2 0 0 1981 6 1 2 0 0 1981 7 1 2 0 0 1981 8 1 2 0 0 1981 9 1 2 0 0 1981 10 1 2 0 0 1981 11 1 2 0 0 1981 12 1 2 0 0 1982 1 1 2 0 0 1982 2 1 2 0 0 1982 3 1 2 0 0 1982 4 1 2 0 0 1982 5 1 2 0 0 1982 6 1 2 0 0 1982 7 1 2 0 0 Miscellanea 9-03-2009 14:42 Pagina 703 704 A. Billi and R. Funiciello Table III. (continued). year month Etna VEI Stromboli VEI Vulcano eruptions eruptions eruptions 1982 8 1 2 0 0 1982 9 1 2 0 0 1982 10 1 2 0 0 1982 11 1 2 0 0 1982 12 1 2 0 0 1983 1 1 2 0 0 1983 2 1 2 0 0 1983 3 1 2 0 0 1983 4 1 2 0 0 1983 5 1 2 0 0 1983 6 1 2 0 0 1983 7 1 2 0 0 1983 8 1 2 0 0 1983 9 1 2 0 0 1983 10 1 2 0 0 1983 11 1 2 0 0 1983 12 1 2 0 0 1984 1 1 2 0 0 1984 2 1 2 0 0 1984 3 1 2 0 0 1984 4 1 2 0 0 1984 5 1 2 0 0 1984 6 1 2 0 0 1984 7 1 2 0 0 1984 8 1 2 0 0 1984 9 1 2 0 0 1984 10 1 2 0 0 1984 11 1 2 0 0 1984 12 1 2 0 0 1985 1 1 2 0 0 1985 2 1 2 0 0 1985 3 1 2 0 0 1985 4 1 2 0 0 1985 5 1 2 0 0 1985 6 1 2 0 0 1985 7 1 2 0 0 1985 8 1 2 0 0 1985 9 1 2 0 0 1985 10 1 2 0 0 1985 11 1 2 0 0 Miscellanea 9-03-2009 14:42 Pagina 704 705 Concurrent eruptions at Etna, Stromboli, and Vulcano: casualty or casuality? Table III. (continued). year month Etna VEI Stromboli VEI Vulcano eruptions eruptions eruptions 1985 12 1 2 1 2 0 1986 1 1 2 1 2 0 1986 2 1 2 1 2 0 1986 3 1 2 1 2 0 1986 4 1 2 1 2 0 1986 5 1 2 0 0 1986 6 1 2 0 0 1986 7 1 2 0 0 1986 8 1 2 0 0 1986 9 1 2 0 0 1986 10 1 2 0 0 1986 11 1 2 0 0 1986 12 1 2 0 0 1987 1 1 2 0 0 1987 2 1 2 0 0 1987 3 1 2 0 0 1987 4 1 2 0 0 1987 5 1 2 0 0 1987 6 1 2 0 0 1987 7 1 2 0 0 1987 8 1 2 0 0 1987 9 1 2 0 0 1987 10 1 2 0 0 1987 11 1 2 0 0 1987 12 1 2 0 0 1988 1 1 2 0 0 1988 2 1 2 0 0 1988 3 1 2 0 0 1988 4 1 2 0 0 1988 5 1 2 0 0 1988 6 1 2 0 0 1988 7 1 2 0 0 1988 8 1 2 0 0 1988 9 1 2 0 0 1988 10 1 2 0 0 1988 11 1 2 0 0 1988 12 1 2 0 0 1989 1 1 2 0 0 1989 2 1 2 0 0 1989 3 1 2 0 0 Miscellanea 9-03-2009 14:42 Pagina 705 706 A. Billi and R. Funiciello Table III. (continued). year month Etna VEI Stromboli VEI Vulcano eruptions eruptions eruptions 1989 4 1 2 0 0 1989 5 1 2 0 0 1989 6 1 2 0 0 1989 7 1 2 0 0 1989 8 1 2 0 0 1989 9 1 2 0 0 1989 10 1 2 0 0 1989 11 1 2 0 0 1989 12 1 2 0 0 1990 1 1 2 0 0 1990 2 1 2 0 0 1990 3 1 2 0 0 1990 4 1 2 0 0 1990 5 1 2 0 0 1990 6 1 2 0 0 1990 7 1 2 0 0 1990 8 1 2 0 0 1990 9 1 2 0 0 1990 10 1 2 0 0 1990 11 1 2 0 0 1990 12 1 2 0 0 1991 1 1 2 0 0 1991 2 1 2 0 0 1991 3 1 2 0 0 1991 4 1 2 0 0 1991 5 1 2 0 0 1991 6 1 2 0 0 1991 7 1 2 0 0 1991 8 1 2 0 0 1991 9 1 2 0 0 1991 10 1 2 0 0 1991 11 1 2 0 0 1991 12 1 2 0 0 1992 1 1 2 0 0 1992 2 1 2 0 0 1992 3 1 2 0 0 1992 4 1 2 0 0 1992 5 1 2 0 0 1992 6 1 2 0 0 1992 7 1 2 0 0 Miscellanea 9-03-2009 14:42 Pagina 706 707 Concurrent eruptions at Etna, Stromboli, and Vulcano: casualty or casuality? Table III. (continued). year month Etna VEI Stromboli VEI Vulcano eruptions eruptions eruptions 1992 8 1 2 0 0 1992 9 1 2 0 0 1992 10 1 2 0 0 1992 11 1 2 0 0 1992 12 1 2 0 0 1993 1 1 2 0 0 1993 2 1 2 0 0 1993 3 1 2 0 0 Table IV. Eruption (with VEI ≥ 2) occurrences by year between 0 and 1993 AD at Etna, Stromboli, and Vulcano. VEI = Volcanic Explosivity Index; 0 = no occurrence; 1 = occurrence. Data are from Simkin and Siebert (1994). year Etna VEI Stromboli VEI Vulcano VEI eruptions eruptions eruptions 252 1 3 0 0 526 0 0 1 3 925 0 0 1 3 1157 1 2 0 0 1160 1 2 0 0 1164 1 2 0 0 1194 1 2 0 0 1222 1 2 0 0 1250 1 2 0 0 1329 1 3 0 0 1333 1 2 0 0 1350 1 2 0 0 1381 1 2 0 0 1408 1 3 0 0 1444 1 2 0 1 3 1536 1 3 0 0 1537 1 2 0 0 1541 1 2 0 0 1550 0 0 1 3 1554 1 2 0 0 1558 0 1 2 0 1566 1 2 0 0 1595 1 3 0 0 Miscellanea 9-03-2009 14:42 Pagina 707 708 A. Billi and R. Funiciello Table IV. (continued). year Etna VEI Stromboli VEI Vulcano VEI eruptions eruptions eruptions 1603 1 2 0 0 1607 1 2 0 0 1610 1 2 0 0 1614 1 2 0 0 1615 1 2 0 0 1616 1 2 0 0 1617 1 2 0 0 1618 1 2 0 0 1619 1 2 0 0 1620 1 2 0 0 1621 1 2 0 0 1622 1 2 0 0 1623 1 2 0 0 1624 1 2 0 0 1626 0 0 1 3 1646 1 2 0 0 1647 1 2 0 0 1669 1 3 0 0 1682 1 2 0 0 1693 1 3 0 0 1694 1 3 0 0 1723 1 2 0 0 1724 1 2 0 0 1727 0 0 1 3 1731 0 0 1 3 1732 1 2 0 1 3 1733 1 2 0 1 3 1734 0 0 1 3 1735 1 2 0 1 3 1736 1 2 0 1 3 1737 0 0 1 3 1738 0 0 1 3 1739 0 0 1 3 1744 1 2 0 0 1745 1 2 0 0 1747 1 2 0 0 Miscellanea 9-03-2009 14:42 Pagina 708 709 Concurrent eruptions at Etna, Stromboli, and Vulcano: casualty or casuality? Table IV. (continued). year Etna VEI Stromboli VEI Vulcano VEI eruptions eruptions eruptions 1748 1 2 0 0 1749 1 2 0 0 1752 1 2 0 0 1753 1 2 0 0 1754 1 2 0 0 1755 1 2 0 0 1756 1 2 0 0 1757 1 2 0 0 1758 1 2 0 0 1759 1 2 0 0 1763 1 3 0 0 1766 1 2 0 0 1768 0 1 2 0 1770 0 1 2 0 1771 0 0 1 3 1778 0 1 2 0 1780 1 2 0 1 2 1781 1 2 0 0 1786 0 0 1 3 1787 1 4 0 0 1791 1 2 0 0 1792 1 3 0 0 1793 1 3 0 0 1797 1 2 0 0 1798 1 2 0 0 1799 1 2 0 0 1800 1 2 0 0 1801 1 2 0 0 1802 1 2 0 0 1803 1 2 0 0 1804 1 2 0 0 1805 1 2 0 0 1806 1 2 0 0 1807 1 2 0 0 1808 1 2 0 0 1809 1 2 0 0 Miscellanea 9-03-2009 14:42 Pagina 709 710 A. Billi and R. Funiciello Table IV. (continued). year Etna VEI Stromboli VEI Vulcano VEI eruptions eruptions eruptions 1811 1 2 0 0 1812 1 2 0 0 1819 1 3 0 0 1822 0 1 3 1 2 1823 0 0 1 2 1828 1 2 0 0 1829 1 2 0 0 1830 1 2 0 0 1831 1 2 0 0 1832 1 2 0 0 1833 1 2 1 2 0 1838 1 2 0 0 1839 1 2 0 0 1842 1 2 0 0 1843 1 2 0 0 1850 0 1 2 0 1852 1 2 0 0 1853 1 2 0 0 1855 0 1 2 0 1856 0 1 2 0 1863 1 2 0 0 1864 1 2 0 0 1865 1 2 1 2 0 1868 1 3 0 0 1873 0 0 1 3 1874 1 2 1 2 1 3 1875 0 0 1 3 1876 0 0 1 3 1877 0 0 1 3 1878 1 2 0 1 3 1879 1 3 1 2 1 3 1880 1 2 0 0 1881 1 2 1 2 0 1882 1 2 1 3 0 1883 1 2 0 0 1885 0 1 2 0 Miscellanea 9-03-2009 14:42 Pagina 710 711 Concurrent eruptions at Etna, Stromboli, and Vulcano: casualty or casuality? Table IV. (continued). year Etna VEI Stromboli VEI Vulcano VEI eruptions eruptions eruptions 1886 1 3 0 1 3 1888 0 1 2 1 3 1889 0 1 2 1 3 1890 0 0 1 3 1891 0 1 3 0 1892 1 2 1 2 0 1893 1 2 1 2 0 1894 1 2 0 0 1895 1 2 1 2 0 1896 1 2 1 2 0 1897 1 2 1 2 0 1898 1 2 1 2 0 1899 1 3 0 0 1900 0 1 2 0 1903 0 1 2 0 1905 0 1 2 0 1906 0 1 2 0 1907 0 1 3 0 1908 1 2 0 0 1910 1 2 0 0 1911 1 2 0 0 1912 1 3 1 2 0 1913 1 2 0 0 1914 1 2 0 0 1915 1 2 1 2 0 1916 1 2 1 2 0 1917 1 2 0 0 1919 1 2 1 3 0 1920 1 2 0 0 1921 1 2 1 2 0 1922 1 2 0 0 1923 1 2 0 0 1930 0 1 3 0 1931 1 2 0 0 1932 1 2 0 0 1933 1 2 0 0 Miscellanea 9-03-2009 14:42 Pagina 711 712 A. Billi and R. Funiciello Table IV. (continued). year Etna VEI Stromboli VEI Vulcano VEI eruptions eruptions eruptions 1934 0 1 2 0 1935 1 2 0 0 1936 1 2 1 2 0 1937 1 2 1 2 0 1938 1 2 1 2 0 1939 1 2 1 2 0 1940 1 3 0 0 1941 1 3 1 2 0 1942 1 3 0 0 1943 0 1 2 0 1944 0 1 2 0 1947 1 2 0 0 1949 1 2 1 2 0 1950 1 2 1 2 0 1951 1 2 1 2 0 1952 0 1 2 0 1953 1 2 0 0 1954 0 1 2 0 1955 1 2 1 2 0 1956 1 2 0 0 1957 1 2 0 0 1958 1 2 0 0 1959 1 3 1 2 0 1960 1 3 0 0 1961 1 3 0 0 1962 1 3 0 0 1963 1 3 0 0 1964 1 3 0 0 1966 1 2 1 2 0 1967 1 2 0 0 1968 1 2 0 0 1969 1 2 0 0 1970 1 2 0 0 1971 1 2 1 2 0 1972 1 2 0 0 1973 1 2 0 0 Miscellanea 9-03-2009 14:42 Pagina 712 713 Concurrent eruptions at Etna, Stromboli, and Vulcano: casualty or casuality? Table IV. (continued). year Etna VEI Stromboli VEI Vulcano VEI eruptions eruptions eruptions 1974 1 2 0 0 1975 1 2 0 0 1976 1 2 0 0 1977 1 2 0 0 1978 1 2 0 0 1979 1 2 0 0 1980 1 3 0 0 1981 1 2 0 0 1982 1 2 0 0 1983 1 2 0 0 1984 1 2 0 0 1985 1 2 1 2 0 1986 1 2 1 2 0 1987 1 2 0 0 1988 1 2 0 0 1989 1 2 0 0 1990 1 2 0 0 1991 1 2 0 0 1992 1 2 0 0 1993 1 2 0 0 Table V. Monthly totals of seismic moment (TM0) for the Etnean and Aeolian areas, from January 1983 to De- cember 2007 (i.e. 300 months). Seismic moments are computed from earthquake magnitudes provided in the IN- GV catalogue of earthquakes available online at www.ingv.it (Bollettino Sismico Italiano, Istituto Nazionale di Geofisica e Vulcanologia). Focal depth for the considered earthquakes is less than 30 km. 0 is where no records are available. year month TM0 Etna (dyn cm) TM0 Aeolian(dyn cm) 1983 Jan. 0 0 1983 Feb. 0 0 1983 Mar. 8.61157E+21 0 1983 Apr. 0 0 1983 May 0 0 1983 Jun. 3.1335E+21 0 1983 Jul. 0 0 1983 Aug. 0 0 Miscellanea 9-03-2009 14:42 Pagina 713 714 A. Billi and R. Funiciello Table V. (continued). year month TM0 Etna (dyn cm) TM0 Aeolian(dyn cm) 1983 Sep. 0 2.21309E+21 1983 Oct. 3.68198E+21 2.21309E+21 1983 Nov. 0 0 1983 Dec. 0 0 1984 Jan. 0 7.53147E+20 1984 Feb. 0 0 1984 Mar. 0 0 1984 Apr. 0 0 1984 May 0 2.78612E+20 1984 Jun. 2.72893E+21 3.9355E+20 1984 Jul. 1.50272E+21 0 1984 Aug. 5.81437E+21 7.85236E+20 1984 Sep. 1.10917E+21 1.56675E+21 1984 Oct. 5.52259E+21 0 1984 Nov. 3.67231E+21 5.55904E+20 1984 Dec. 0 0 1985 Jan. 0 0 1985 Feb. 1.1714E+21 0 1985 Mar. 4.33707E+21 0 1985 Apr. 1.343E+21 0 1985 May 0 0 1985 Jun. 3.9355E+20 0 1985 Jul. 0 0 1985 Aug. 5.55904E+20 0 1985 Sep. 3.12608E+21 3.9355E+20 1985 Oct. 2.21835E+21 0 1985 Nov. 2.08488E+21 0 1985 Dec. 1.68442E+22 9.24872E+20 1986 Jan. 6.15005E+21 0 1986 Feb. 1.97242E+20 0 1986 Mar. 1.13198E+21 3.9355E+20 1986 Apr. 2.78612E+20 0 1986 May 7.10694E+21 2.21309E+21 1986 Jun. 3.77467E+20 1.97242E+20 1986 Jul. 3.26358E+21 0 Miscellanea 9-03-2009 14:42 Pagina 714 715 Concurrent eruptions at Etna, Stromboli, and Vulcano: casualty or casuality? Table V. (continued). year month TM0 Etna (dyn cm) TM0 Aeolian(dyn cm) 1986 Aug. 4.75854E+20 0 1986 Sep. 1.35443E+21 1.97242E+20 1986 Oct. 1.96846E+22 7.94256E+21 1986 Nov. 2.23793E+21 0 1986 Dec. 2.48313E+19 0 1987 Jan. 2.38492E+20 0 1987 Feb. 4.05612E+21 4.9545E+19 1987 Mar. 0 0 1987 Apr. 0 0 1987 May 6.76753E+20 9.88553E+19 1987 Jun. 9.88553E+19 0 1987 Jul. 4.18381E+20 0 1987 Aug. 1.12675E+21 2.96191E+20 1987 Sep. 8.84091E+20 5.55904E+20 1987 Oct. 6.99842E+19 9.88553E+19 1987 Nov. 3.28157E+20 0 1987 Dec. 4.9545E+19 2.67695E+20 1988 Jan. 3.13687E+20 0 1988 Feb. 3.50752E+19 0 1988 Mar. 0 5.18173E+21 1988 Apr. 1.40989E+21 2.36029E+21 1988 May 0 3.23671E+21 1988 Jun. 1.27126E+21 3.84779E+21 1988 Jul. 2.43216E+20 0 1988 Aug. 2.70863E+21 4.7803E+21 1988 Sep. 1.75792E+19 4.9545E+19 1988 Oct. 6.99842E+19 1.44361E+20 1988 Nov. 6.27679E+20 6.99842E+19 1988 Dec. 7.96041E+20 9.88553E+19 1989 Jan. 7.56663E+20 3.50752E+19 1989 Feb. 3.44341E+21 5.58018E+20 1989 Mar. 3.34351E+20 1.6884E+20 1989 Apr. 2.18737E+20 1.05059E+20 1989 May 6.41844E+20 2.18385E+20 1989 Jun. 2.37224E+21 1.39637E+20 Miscellanea 9-03-2009 14:42 Pagina 715 716 A. Billi and R. Funiciello Table V. (continued). year month TM0 Etna (dyn cm) TM0 Aeolian(dyn cm) 1989 Jul. 3.64362E+21 1.41525E+21 1989 Aug. 1.28044E+22 2.44696E+20 1989 Sep. 5.81645E+21 6.72162E+20 1989 Oct. 7.8372E+21 2.83997E+20 1989 Nov. 1.56675E+21 6.71243E+19 1989 Dec. 6.99842E+19 6.99842E+19 1990 Jan. 3.2323E+20 0 1990 Feb. 2.3495E+20 1.19391E+21 1990 Mar. 1.07113E+22 2.52683E+21 1990 Apr. 5.3811E+20 3.34819E+20 1990 May 1.63593E+21 4.9545E+19 1990 Jun. 2.78612E+20 0 1990 Jul. 6.50577E+20 0 1990 Aug. 1.43476E+21 2.48313E+19 1990 Sep. 3.21509E+21 1.63863E+21 1990 Oct. 1.69074E+20 4.18381E+20 1990 Nov. 7.01504E+19 1.05059E+20 1990 Dec. 4.36437E+20 0 1991 Jan. 2.78516E+21 1.69192E+20 1991 Feb. 3.80765E+20 0 1991 Mar. 1.39637E+20 0 1991 Apr. 1.58196E+21 7.03374E+20 1991 May 2.62578E+21 0 1991 Jun. 5.05719E+20 0 1991 Jul. 4.21968E+20 4.9545E+19 1991 Aug. 3.28049E+20 5.99065E+19 1991 Sep. 3.6788E+21 2.92271E+21 1991 Oct. 8.92828E+20 0 1991 Nov. 2.92217E+20 6.99842E+19 1991 Dec. 7.58078E+20 0 1992 Jan. 1.2995E+20 6.99842E+19 1992 Feb. 6.82522E+20 6.99842E+19 1992 Mar. 6.99842E+19 1.25758E+21 1992 Apr. 1.75792E+19 9.48155E+19 1992 May 3.45643E+20 1.40218E+20 Miscellanea 9-03-2009 14:42 Pagina 716 717 Concurrent eruptions at Etna, Stromboli, and Vulcano: casualty or casuality? Table V. (continued). year month TM0 Etna (dyn cm) TM0 Aeolian(dyn cm) 1992 Jun. 1.19813E+20 1.41266E+20 1992 Jul. 1.97242E+20 4.28625E+20 1992 Aug. 9.88553E+19 1.39637E+20 1992 Sep. 1.57216E+20 1.89513E+20 1992 Oct. 0 0 1992 Nov. 0 4.63534E+20 1992 Dec. 0 3.9355E+20 1993 Jan. 0 2.58995E+21 1993 Feb. 6.99842E+19 4.9545E+19 1993 Mar. 4.9545E+19 2.28308E+21 1993 Apr. 1.19529E+20 1.97242E+20 1993 May 1.48635E+20 3.78461E+20 1993 Jun. 4.98609E+20 0 1993 Jul. 9.50481E+20 1.25316E+21 1993 Aug. 3.50456E+21 5.90792E+20 1993 Sep. 4.96627E+19 1.20803E+21 1993 Oct. 4.9545E+19 5.92524E+20 1993 Nov. 0 0 1993 Dec. 2.79274E+20 0 1994 Jan. 0 0 1994 Feb. 1.8968E+20 8.46202E+19 1994 Mar. 4.9545E+19 5.83666E+20 1994 Apr. 9.88553E+19 2.48313E+19 1994 May 1.42953E+21 5.05719E+20 1994 Jun. 8.47035E+19 6.99842E+19 1994 Jul. 5.99065E+19 4.70778E+21 1994 Aug. 6.99842E+19 0 1994 Sep. 2.53066E+21 1.44361E+20 1994 Oct. 3.89057E+20 2.94814E+21 1994 Nov. 2.80103E+20 5.59765E+21 1994 Dec. 7.81624E+20 5.92299E+20 1995 Jan. 1.75792E+19 9.88553E+19 1995 Feb. 6.44712E+21 2.38492E+20 1995 Mar. 0 0 1995 Apr. 0 3.58021E+20 Miscellanea 9-03-2009 14:42 Pagina 717 718 A. Billi and R. Funiciello Table V. (continued). year month TM0 Etna (dyn cm) TM0 Aeolian(dyn cm) 1995 May 3.19881E+20 0 1995 Jun. 9.48155E+19 0 1995 Jul. 1.39637E+20 5.6121E+22 1995 Aug. 8.22263E+20 1.25151E+22 1995 Sep. 2.48313E+19 5.33685E+20 1995 Oct. 2.38727E+20 9.51834E+20 1995 Nov. 9.88553E+19 4.9545E+19 1995 Dec. 7.87947E+19 0 1996 Jan. 9.909E+19 4.35734E+20 1996 Feb. 2.64367E+20 1.97242E+20 1996 Mar. 1.23687E+20 1.39637E+20 1996 Apr. 1.34014E+20 0 1996 May 0 5.7471E+20 1996 Jun. 9.48155E+19 1.38779E+21 1996 Jul. 6.99842E+19 8.24451E+20 1996 Aug. 1.2659E+21 1.97242E+20 1996 Sep. 6.27505E+20 6.25888E+20 1996 Oct. 0 0 1996 Nov. 5.23153E+20 0 1996 Dec. 2.12613E+21 0 1997 Jan. 3.36345E+21 3.9355E+20 1997 Feb. 4.74944E+21 8.45102E+20 1997 Mar. 4.92758E+20 1.25972E+21 1997 Apr. 1.25142E+21 0 1997 May 7.16238E+20 1.77135E+21 1997 Jun. 7.73346E+20 9.88553E+19 1997 Jul. 7.36677E+20 1.05059E+20 1997 Aug. 4.40469E+21 0 1997 Sep. 2.60291E+21 2.42808E+21 1997 Oct. 3.8698E+21 1.75792E+19 1997 Nov. 9.91181E+20 2.3411E+21 1997 Dec. 2.50586E+22 3.48596E+20 1998 Jan. 2.10765E+22 0 1998 Feb. 3.9807E+20 8.70253E+20 1998 Mar. 4.77556E+21 0 Miscellanea 9-03-2009 14:42 Pagina 718 719 Concurrent eruptions at Etna, Stromboli, and Vulcano: casualty or casuality? Table V. (continued). year month TM0 Etna (dyn cm) TM0 Aeolian(dyn cm) 1998 Apr. 2.34619E+20 9.12398E+19 1998 May 2.2054E+21 0 1998 Jun. 6.07607E+20 6.79591E+20 1998 Jul. 2.38492E+20 4.43095E+20 1998 Aug. 1.0944E+21 1.39968E+20 1998 Sep. 6.75551E+20 5.7471E+20 1998 Oct. 4.30705E+20 0 1998 Nov. 1.44361E+20 0 1998 Dec. 2.34753E+21 0 1999 Jan. 6.46722E+20 4.18249E+20 1999 Feb. 2.18658E+21 6.53665E+20 1999 Mar. 2.01256E+21 2.59166E+20 1999 Apr. 5.63324E+20 1.97242E+20 1999 May 4.01157E+20 1.6884E+20 1999 Jun. 9.30161E+20 0 1999 Jul. 1.73232E+20 0 1999 Aug. 3.52873E+21 3.9355E+20 1999 Sep. 6.42838E+20 1.74712E+20 1999 Oct. 1.55728E+21 1.23687E+20 1999 Nov. 1.484E+20 0 1999 Dec. 4.18381E+20 2.01055E+20 2000 Jan. 1.3795E+21 0 2000 Feb. 1.93858E+21 0 2000 Mar. 1.71442E+20 0 2000 Apr. 6.5476E+20 2.54997E+21 2000 May 2.46787E+20 0 2000 Jun. 0 1.39637E+20 2000 Jul. 5.34921E+20 4.28625E+20 2000 Aug. 2.92692E+20 0 2000 Sep. 9.89385E+20 1.39637E+20 2000 Oct. 6.02056E+20 6.99842E+19 2000 Nov. 1.68763E+22 0 2000 Dec. 1.29617E+21 0 2001 Jan. 2.26636E+21 0 2001 Feb. 5.35177E+20 1.97242E+20 Miscellanea 9-03-2009 14:42 Pagina 719 720 A. Billi and R. Funiciello Table V. (continued). year month TM0 Etna (dyn cm) TM0 Aeolian(dyn cm) 2001 Mar. 7.57161E+20 0 2001 Apr. 5.69959E+21 0 2001 May 4.65916E+21 1.75792E+19 2001 Jun. 3.43712E+20 4.9545E+19 2001 Jul. 5.18235E+22 1.14118E+22 2001 Aug. 1.68645E+21 8.69404E+20 2001 Sep. 2.48313E+19 8.5522E+20 2001 Oct. 5.96325E+21 5.69665E+20 2001 Nov. 0 7.85236E+20 2001 Dec. 6.99842E+19 0 2002 Jan. 3.28157E+20 0 2002 Feb. 1.74712E+20 1.39637E+20 2002 Mar. 3.28819E+20 1.3422E+21 2002 Apr. 2.09621E+20 9.86941E+21 2002 May 2.14345E+20 2.78612E+20 2002 Jun. 1.89513E+20 8.34516E+20 2002 Jul. 7.30429E+20 0 2002 Aug. 1.53444E+21 1.39637E+20 2002 Sep. 2.46787E+20 6.95541E+20 2002 Oct. 1.07678E+23 1.19529E+20 2002 Nov. 5.43328E+21 0 2002 Dec. 2.25681E+21 3.50752E+19 2003 Jan. 1.6884E+20 0 2003 Feb. 8.95013E+21 2.78612E+20 2003 Mar. 2.09621E+20 2.48313E+19 2003 Apr. 0 0 2003 May 1.39968E+20 0 2003 Jun. 1.97242E+20 5.75371E+20 2003 Jul. 1.95985E+21 0 2003 Aug. 2.78612E+20 0 2003 Sep. 0 0 2003 Oct. 2.18385E+20 0 2003 Nov. 0 1.6884E+20 2003 Dec. 1.6884E+20 0 2004 Jan. 2.32317E+20 1.6884E+20 Miscellanea 9-03-2009 14:42 Pagina 720 721 Concurrent eruptions at Etna, Stromboli, and Vulcano: casualty or casuality? Table V. (continued). year month TM0 Etna (dyn cm) TM0 Aeolian(dyn cm) 2004 Feb. 7.65504E+20 0 2004 Mar. 8.92783E+20 2.50113E+21 2004 Apr. 0 3.17562E+21 2004 May 7.57776E+20 2.39508E+20 2004 Jun. 2.20707E+21 6.99842E+19 2004 Jul. 1.39578E+21 1.14425E+21 2004 Aug. 2.38824E+20 0 2004 Sep. 7.43764E+19 5.99065E+19 2004 Oct. 3.50752E+19 5.07524E+20 2004 Nov. 9.88553E+19 8.46202E+19 2004 Dec. 6.99842E+19 0 2005 Jan. 1.97242E+20 7.85236E+20 2005 Feb. 1.39637E+20 0 2005 Mar. 0 0 2005 Apr. 4.97243E+20 6.23735E+18 2005 May 9.48155E+19 3.10687E+19 2005 Jun. 4.38857E+19 1.79728E+19 2005 Jul. 3.44522E+21 1.75792E+19 2005 Aug. 1.42534E+21 4.24106E+19 2005 Sep. 3.50752E+19 1.24451E+19 2005 Oct. 7.30334E+21 1.45584E+21 2005 Nov. 2.63897E+19 3.61799E+20 2005 Dec. 7.227E+20 2.78612E+20 2006 Jan. 9.03744E+21 2.38166E+19 2006 Feb. 2.84242E+20 5.26544E+19 2006 Mar. 1.74146E+21 7.01504E+19 2006 Apr. 4.97334E+19 6.19877E+20 2006 May 6.12295E+21 4.58971E+21 2006 Jun. 6.12458E+21 4.17313E+20 2006 Jul. 2.22845E+20 1.10445E+19 2006 Aug. 2.56611E+20 1.62649E+21 2006 Sep. 8.24293E+19 3.0517E+20 2006 Oct. 1.55791E+20 5.70032E+20 2006 Nov. 7.19683E+20 3.23731E+19 2006 Dec. 1.84017E+22 3.42244E+21 Miscellanea 9-03-2009 14:42 Pagina 721 722 A. Billi and R. Funiciello REFERENCES ACOCELLA, V., B. BEHNCKE, M. NERI and S. D’AMICO (2003): Link between major flank slip and 2002–2003 eruption at Mt. Etna (Italy), Geophy. Res. Lett., 30, 2286, doi: 10.1029/2003GL018642. ALPARONE, S., B. BEHNCKE, S. GIAMMANCO, M. NERI and E. PRIVITERA (2005): Paroxysmal summit activity at Mt. Etna (Italy) monitored through continuous soil radon measurements, Geophys. Res. Lett., 32, L16307, doi: 10.1029/2005GL023352. AZZARO, R., M.S. BARBANO, R. RIGANO and S. VINCIGUER- RA (2001): Time seismicity patterns affecting local and regional fault systems in the Etna region: preliminary results for the period 1874-1913, J. Geol. Soc., Lond., 158, 561-572. BARATTA, M. (1901): I terremoti d’Italia (Arnoldo Forni Editore, Bologna). BARBERI, G., O. COCINA, G. NERI, E. PRIVITERA and S. SPAMPINATO (2000): Volcanological inferences from seismic-strain tensor computations at Mt. Etna Vol- cano, Sicily, Bull. Volcanol., 62, 318-330. BARRIENTOS, S.E. (1994): Large thrust earthquakes and vol- canic eruptions, Pure Appl. Geophys., 142, 225-237. BASILI, R., G. VALENSISE, P. VANNOLI, P. BURRATO, U. FRA- CASSI, S. MARIANO, M.M. TIBERTI and E. BOSCHI (2008): The Database of Individual Seismogenic Sources (DISS), version 3: summarizing 20 years of re- search on Italy’s earthquake geology, Tectonophysics, 453, 20-43. BAUTISTA, B.C., M.L.P. BAUTISTA, R.S. STEIN, E.S. BARCELONA, R.S. PUNONGBAYAN, E.P. LAGUERTA, A.R. RASDAS, G. AMBUBUYOG and E.Q. AMIN (1996): Rela- tionship of regional and local structures to Mount Pinatubo activity, in Fire and Mud: Eruptions and La- hars of Mount Pinatubo, Philippines, edited by NEWHALL, C.G. and R.S. PUNONGBAYAN (University of Washington Press, Washington, D.C.), pp. 351-369. BEBBINGTON, M.S. and C.D. LAI (1996): Statistical analysis of New Zealand volcanic occurrence data, J. Volcanol. Geoth. Res., 74, 101-110. BEHNCKE, B. (2001): Volcanism in the Southern Apennines and Sicily, in Anatomy of an Orogen: the Apennines and Adjacent Mediterranean Basins, edited by VAI, G.B. and I.P. MARTINI (Kluwer Academic Publishers, Dordrecht), pp. 105-120. BILLI, A., G. BARBERI, C. FACCENNA, G. NERI, F. PEPE and A. SULLI (2006): Tectonics and seismicity of the Tindari Fault System, southern Italy: crustal deformations at the transition between ongoing contractional and extension- al domains located above the edge of a subducting slab, Tectonics, 25, TC2006, doi: 10.1029/2004TC001763. BILLI A., D. PRESTI, C. FACCENNA, G. NERI and B. OREC- CHIO (2007): Seismotectonics of the Nubia plate com- pressive margin in the south Tyrrhenian region, Italy: clues for subduction inception, J. Geophys. Res., 112, B08302, doi: 10.1029/2006JB004837. BOSCHI, E., E. GUIDOBONI, G. FERRARI, G. VALENSISE and P. GASPERINI (1997): Catalogo dei forti terremoti in Italia dal 461 a.C. al 1990, (Istituto Nazionale di Geofisica, Roma e Storia Geofisica e Ambiente, Bologna). BRANCA, S., M. COLTELLI, E. DE BENI and J. WIJBRANS (2008): Geological evolution of Mount Etna volcano (Italy) from earliest products until the first central vol- canism (between 500 and 100 ka ago) inferred from geochronological and stratigraphic data, Int. J. Earth Sci., 97, 135-152. BRODSKY, E., B. STURTEVANT and H. KANAMORI (1998): Earthquakes, volcanoes, and rectified diffusion, J. Geo- phys. Res., 103, 23827-23838. Table V. (continued). year month TM0 Etna (dyn cm) TM0 Aeolian(dyn cm) 2007 Jan. 1.75792E+19 1.39637E+20 2007 Feb. 1.66358E+20 0 2007 Mar. 6.99842E+19 3.04503E+20 2007 Apr. 3.07995E+20 2.30905E+20 2007 May 4.97951E+20 3.9762E+21 2007 Jun. 2.11475E+20 1.2484E+20 2007 Jul. 4.4157E+18 9.56001E+20 2007 Aug. 4.98609E+20 4.57858E+20 2007 Sep. 1.75792E+19 3.45058E+21 2007 Oct. 2.96098E+20 2.60874E+20 2007 Nov. 5.99065E+19 1.64468E+20 2007 Dec. 7.95694E+19 1.39637E+20 Miscellanea 9-03-2009 14:42 Pagina 722 723 Concurrent eruptions at Etna, Stromboli, and Vulcano: casualty or casuality? BRODSKY, E., V. KARAKOSTAS and H. KANAMORI (2000): A new observation of dynamically triggered regional seismicity: earthquakes in Greece following the Au- gust, 1999 Izmit, Turkey earthquake, Geophys. Res. Lett., 27, 2741-2744. CALIRO, S., A. CARACAUSI, G. CHIODINI, M. DITTA, F. ITAL- IANO, M. LONGO, C. MINOPOLI, P.M. NUCCIO, A. PAONI- TA and A. RIZZO (2004): Evidence of a recent input of magmatic gases into the quiescent volcanic edifice of Panarea, Aeolian Islands, Italy, Geophys. Res. Lett., 31, L07619, doi: 10.1029/2003GL019359. CALVARI, S., L. SPAMPINATO, L. LODATO, A.J.L. HARRIS, M.R. PATRICK, J. DEHN and M.R. BURTON (2005): Chronology and complex volcanic processes during the 2002-2003 flank eruption at Stromboli volcano (Italy) reconstructed from direct observations and surveys with a handheld thermal camera, J. Geophys. Res., 110, B02201, doi: 10.1029/2004JB003129. CARDACI, C., S. FALSAPERLA, P. GASPERINI, G. LOMBARDO, W. MARZOCCHI and F. MULARGIA (1993): Crosscorrela- tion analysis of seismic and volcanic data at Mt Etna volcano, Italy, Bull. Volcanol., 55, 596-603. CARR, M.J. (1977): Volcanic activity and great earthquakes at convergent plate margins, Science, 197, 655-657. CIGOLINI, C., M. LAIOLO and D. COPPOLA (2007): Earth- quake-volcano interactions detected from radon de- gassing at Stromboli (Italy), Earth Planet. Sci. Lett., 257, 511-525. D’AGOSTINO, N. and G. SELVAGGI (2004): Crustal motion along the Eurasia-Nubia plate boundary in the Calabri- an Arc and Sicily and active extension in the Messina Straits from GPS measurements, J. Geophys. Res., 109, B11402, doi: 10.1029/2004JB002998. DE DOLOMIEU, D.G. (1783): Voyage aux Iles de Lipari fait en 1781, (Cuchet, Paris). DELLINO, P. and K. KYRIAKOPOULOS (2003): Phreatomag- matic ash from the ongoing eruption of Etna reaching the Greek island of Cefalonia, J. Volcanol. Geoth. Res., 126, 341-345. DEWEY, J.F., M.L. HELMAN, E. TURCO, D.H.W. HUTTON and D. KNOTT (1989): Kinematics of the western Mediter- ranean, in Alpine Tectonics, edited by COWARD, M.P., D. DIETRICH and R.G. PARK, Geological Society Spe- cial Publication, 45, 265-283. ESPOSITO, A., G. GIORDANO and M. ANZIDEI (2006): The 2002-2003 submarine gas eruption at Panarea volcano (Aeolian Islands, Italy): volcanology of the seafloor and implications for the hazard scenario, Mar. Geol., 227, 119-134. FACCENNA, C., C. PIROMALLO, A. CRESPO-BLANC and L. JO- LIVET (2004): Lateral slab deformation and the origin of the western Mediterranean arcs, Tectonics, 23, TC1012, doi: 10.1029/2002TC001488. FACCENNA, C., L. CIVETTA, M. D’ANTONIO, F. FUNICIELLO, L. MARGHERITI and C. PIROMALLO (2005): Constraints on mantle circulation around the deforming Calabrian slab, Geophys. Res. Lett., 32, L06311, doi: 10.1029/2004GL021874. FEUILLET, N., M. COCCO, C. MUSUMECI and C. NOSTRO (2006): Stress interaction between seismic and vol- canic activity at Mt Etna, Geophys. J. Int., 164, 697- 718. FRAZZETTA, G., P.Y. GILLOT, L. LA VOLPE and M.F. SHERI- DAN (1984): Volcanic hazards at Fossa of Vulcano: da- ta from the last 6000 years, Bull. Volcanol., 47, 105- 124. FOUQUÉ, F.A. (1865): Sur l’eruption de l’Etna du 1 fevrier 1865, Comptes Rendus de l’Academie des Sciences, 61, 210-211. GABBIANELLI, G., C. ROMAGNOLI, P.L. ROSSI and N. CALANCHI (1993): Marine geology of the Panarea- Stromboli area (Aeolian Archipelago, Southern Tyrrhenian sea), Acta Vulcanologica, 3, 11-20. GHISETTI, F. (1979): Relazioni tra strutture e fasi trascorren- ti e distensive lungo i sistemi Messina-Fiumefreddo, Tindari-Letojanni e Alia-Malvagna (Sicilia nord-orien- tale): uno studio microtettonico, Geologica Romana, 18, 23-58. GILLOT, P.Y., G. KIEFFER and R. ROMANO (1994): The evo- lution of Mount Etna in the light of potassium-argon dating, Acta Vulcanologica, 5, 81-87. GLASBY, G.P. and J. KASAHARA (2001): Influence of tidal effects on the periodicity of earthquake activity in di- verse geological settings with particular emphasis on submarine hydrothermal systems, Earth-Sci. Rev., 52, 261-297. GOES, S., D. GIARDINI, S. JENNY, C. HOLLENSTEIN, H.G. KAHLE and A. GEIGER (2004), A recent tectonic reor- ganization in the south-central Mediterranean, Earth Planet. Sci. Lett., 226, 335-345. GUDMUNDSSON, A. (2006): How local stresses control mag- ma-chamber ruptures, dyke injections, and eruptions in composite volcanoes, Earth-Sci. Rev., 79, 1-31. GUDMUNDSSON, A. and S.L. BRENNER (2003): Loading of a seismic zone to failure deforms nearby volcanoes: a new earthquake precursor, Terra Nova, 15, 187-193. GUDMUNDSSON, A. and R.E.B. ANDREW (2007): Mechanical interaction between active volcanoes in Iceland, Geophys. Res. Lett., 34, L10310, doi: 10.1029/2007GL029873. GVIRTZMAN, Z. and A. NUR (1999): The formation of Mount Etna as the consequence of slab rollback, Na- ture, 401, 782-785. GVIRTZMAN, Z. and A. NUR (2001): Residual topography, lithospheric structure and sunken slabs in the central Mediterranean, Earth Planet. Sci. Lett., 187, 117-130. HANKS, T.C. and H. KANAMORI (1979): A moment-magni- tude scale, J. Geophys. Res., 84, 2348-2350. HARRIS, A.J.L. and M. RIPEPE (2007): Regional earthquake as a trigger for enhanced volcanic activity: evidence from MODIS thermal data, Geophys. Res. Lett., 34, L02304, doi: 10.1029/2006GL028251. JACQUES, E., G.C.P. KING, P. TAPPONNIER, J.C. RUEGG and I. MANIGHETTI (1996): Seismic activity triggered by stress changes after the 1978 events in the Asal rift, Djibouti, Geophys. Res. Lett., 23, 2481-2484. JAQUET, O. and R. CARNIEL (2006): Estimation of volcanic hazards using geostatistical models, in Statistics in Vol- canology edited by: H. MADER, S. COLES, C. CONNOR and L. CONNOR, (IAVCEI Publications IAV001, Geo- logical Society of London), pp. 89-104 KANAMORI, H. and J.W. GIVENS (1982): Analysis of long period seismic waves excited by the May 18, eruption of Mount St. Helens: a terrestrial monopole?, J. Geo- phys. Res., 87, 5422-5432. KIMURA, J. (1996): Near-synchronicity and periodicity of back-Arc propagation of Quaternary explosive volcan- Miscellanea 9-03-2009 14:42 Pagina 723 724 A. Billi and R. Funiciello ism in the southern segment of Northeastern Honshu Arc, Japan: A study facilitated by tephrochronology, Quat. Int., 34-36, 99-105. KLEIN, F.W. (1982): Patterns of historical eruptions at Hawaiian volcanoes, J. Volcanol. Geoth. Res., 12, 1-35. LANZAFAME, G., M. NERI, V. ACOCELLA, A. BILLI, R. FUNI- CIELLO and G. GIORDANO (2003): Structural features of the July-August 2001 Mount Etna eruption: evidence for a complex magma supply system, J. Geol. Soc., London, 160, 531-544. LEMARCHAND, N. and J.-R. GRASSO (2007): Interactions be- tween earthquakes and volcano activity, Geophys. Res. Lett., 34, L24303, doi: 10.1029/2007GL031438. LINDE, A.T. and I.S. SACKS (1998): Triggering of volcanic eruptions, Nature, 395, 888-890. MADONIA, P., C. FEDERICO, P. CUSANO, S. PETROSINO, A. AIUPPA and S. GURRIERI (2008): Crustal dynamics of Mount Vesuvius from 1998 to 2005: Effects on seis- micity and fluid circulation, J. Geophys. Res., 113, B05206, doi: 10.1029/2007JB005210. MALINVERNO, A. and W.B.F. RYAN (1986): Extension in the Tyrrhenian Sea and shortening in the Apennines as re- sult of arc migration driven by sinking of the litho- sphere, Tectonics, 5, 227-254. MANGA, M. (2007): Did an earthquake trigger the May 2006 eruption of the Lusi Mud Volcano?, Eos Transac- tions of the American Geophysical Union, 88, 201, doi: 10.1029/2007EO180009. MANGA, M. and E. BRODSKY (2006): Seismic triggering of eruptions in the far field: volcanoes and geysers, Annu. Rev. Earth Planet. Sci., 34, 263-291. MARZOCCHI, W., R. SCANDONE and F. MULARGIA (1993): The tectonic setting of Mount Vesuvius and the correlation between its eruptions and the earthquakes of the south- ern Apennines, J. Volcanol. Geoth. Res., 58, 27-41. MARZOCCHI, W., E. CASAROTTI and A. PIERSANTI (2002): Mod- eling the stress variations induced by great earthquakes on the largest volcanic eruptions of the 20th century, J. Geo- phys. Res., 107, 2320, doi: 10.1029/2001JB001391. MARZOCCHI, W., ZACCARELLI, L. and E. BOSCHI (2004): Phenomenological evidence in favor of a remote seis- mic coupling for large volcanic eruptions, Geophys. Res. Lett., 31, L04601, doi: 10.1029/2003GL018709. MCNUTT, S.R. (1999): Eruptions of Pavolf Volcano, Alas- ka, and their possible modulation by ocean load and tectonic stresses: re-evaluation of the hypothesis based on new data from 1984-1998, Pure Appl. Geophys., 155, 701-712. MCNUTT, S.R. and R.J. BEAVAN (1987): Eruptions of Pavlof Volcano and their possible modulation by ocean load and tectonic stresses, J. Geophys. Res., 92, 11509- 11523. MELLORS, R., D. KILB, A. ALIYEV, A. GASANOV and G. YE- TIRMISHLI (2007): Correlations between earthquakes and large mud volcano eruptions, J. Geophys. Res., 112, B04304, doi: 10.1029/2006JB004489. MERCALLI, G. (1879): Contribuzioni alla geologia delle Isole Lipari, Atti della Società Italiana di Scienze Na- turali, 22, 369-380. MERCALLI, G. (1888): L’Isola Vulcano e lo Stromboli dal 1886 al 1888, Atti della Società Italiana di Scienze Naturali, 31, 1-15. MIKLIUS, A. and P. CERVELLI (2003), Interaction between Kilauea and Mauna Loa, Nature, 421, 229. MONTELLI, R., G. NOLET, F.A. DAHLEN, G. MASTERS, E.R. ENGDAHL and S.-H. HUNG (2004): Finite-frequency to- mography reveals a variety of plumes in the mantle, Science, 303, 338-343. MONTONE, P., M.T. MARIUCCI, S. PONDRELLI and A. AMATO (2004): An improved stress map for Italy and surround- ing regions (Central Mediterranean), J. Geophys. Res., 109, B10410. doi: 10.1029/2003JB002703. MULARGIA, F., S. TINTI and E. BOSCHI (1985): A statistical analysis of flank eruptions on Etna volcano, J. Vol- canol. Geoth. Res., 23, 263-272 MULARGIA, F., P. GASPERINI and W. MARZOCCHI (1991): Pattern recognition applied to volcanic activity: identi- fication of the precursory patterns to Etna recent flank eruptions and periods of rest., J. Volcanol. Geoth. Res., 45, 187-196. NERCESSIAN, A., A. HIRN and M. SAPIN (1991): A correla- tion between earthquakes and eruptive phases at Mt Et- na: an example and past occurrences, Geophys. J. Int., 105, 131-138. NERI, G., G. BARBERI, B. ORECCHIO and A. MOSTACCIO (2003): Seismic strain and seismogenic stress regimes in the crust of the southern Tyrrhenian region, Earth Planet. Sci. Lett., 213, 97-112. NERI, G., G. BARBERI, G. OLIVA and B. ORECCHIO (2005): Spatial variations of seismogenic stress orientations in Sicily, south Italy, Phys. Earth Planet. Int., 148, 175- 191. NERI, G., G. OLIVA, B. ORECCHIO and D. PRESTI (2006): Possible seismic gap within a highly seismogenic belt crossing Calabria and Eastern Sicily, Italy, Bull. Seism. Soc. Am., 96, 1321-1331. NEWHALL, C.F. and S. SELF (1982): The volcanic explosiv- ity index (VEI): an estimate of explosive Magnitude for historical eruptions, J. Geophys. Res., 87, 1231-1238. NOSTRO, C., R.S. STEIN, M. COCCO, M.E. BELARDINELLI and W. MARZOCCHI (1998): Two-way coupling between Vesuvius eruptions and southern Apennine earth- quakes, Italy, by elastic stress transfer, J. Geophys. Res., 103, 24487, doi: 10.1029/98JB00902. OHTAKE, M. and H. NAKAHARA (1999): Seasonality of great earthquake occurrence at the northeastern margin of the Philippine Sea plate, Pure Appl. Geophys., 155, 689-700. PATACCA, E., R. SARTORI and P. SCANDONE (1992): Tyrrhen- ian basin and Apenninic arcs: kinematic relations since late Tortonian times, Mem. Soc. Geol. It., 45, 425-451. PATANÈ, D., P. DE GORI, C. CHIARABBA and A. BONACCOR- SO (2003): Magma ascent and the pressurization of Mount Etna’s volcanic system, Science, 299, 2061- 2063. PONDRELLI, S., C. PIROMALLO and E. SERPELLONI (2004): Convergence vs. retreat in Southern Tyrrhenian Sea: Insights from kinematics, Geophys. Res. Lett., 31, L06611, doi: 10.1029/2003GL019223. RIPEPE, M., E. MARCHETTI, G. ULIVIERI, A. HARRIS, J. DEHN, M. BURTON, T. CALTABIANO and G. SALERNO (2005): Effusive to explosive transition during the 2003 eruption of Stromboli volcano, Geology, 33, 341-344. RITTMANN, A. (1931): Der Ausbruch des Stromboli am 11 September 1930, Zeitschrift für Vulkanologie, 14, 47-77. RITTMANN, A. (1964): Vulkanismus und Tektonik des Ätna, Miscellanea 9-03-2009 14:42 Pagina 724 725 Concurrent eruptions at Etna, Stromboli, and Vulcano: casualty or casuality? Geologische Rundschau, 53, 788-800. SHARP, A.D.L., G. LOMBARDO and P.M. DAVIS (1981): Cor- relation between eruptions of Mount Etna, Sicily, and regional earthquakes as seen in historical records from AD 1582, Geophys. J. Int., 65, 507-523. SIEBERT, L. and T. SIMKIN (2002): Volcanoes of the World: an Illustrated Catalog of Holocene Volcanoes and their Eruptions. Smithsonian Institution, Global Volcanism Program Digital Information Series, GVP-3, (http://www.volcano.si.edu/world/). SILVESTRI, O. (1867): I fenomeni vulcanici presentati dal- l’Etna nel 1863-64-65-66, Atti dell’Accademia Gioenia di Scienze Naturali in Catania, 23, 55-317. SILVESTRI, O. (1890): Etna, Sicilia ed isole vulcaniche adi- acenti sotto il punto di vista dei fenomeni eruttivi e ge- odinamici avvenuti durante l’anno 1889, Atti dell’Ac- cademia Gioenia di Scienze Naturali in Catania, 66, 222-249. SILVESTRI, O. (1893): L’eruzione dell’Etna del 1886, Atti dell’Accademia Gioenia di Scienze Naturali in Cata- nia, 69, 1-37. SIMKIN, T. and L. SIEBERT (1994): Volcanoes of the World, (Geoscience Press, Tucson). TANGUY, J.-C., M. CONDOMINES, M. LE GOFF, V. CHILLEMI, S. LA DELFA and G. PATANÈ (2007): Mount Etna erup- tions of the last 2,750 years: revised chronology and lo- cation through archeomagnetic and 226Ra-230Th dating, Bull. Volcanol., 70, 55-83. TORTORICI, L., G. VENTURA, R. MAZZUOLI and C. MONACO (1995): Strutture del settore orientale dell’Arcipelago Eoliano: interpretazione tettonica e modellizzazione numerica, Studi Geologici Camerti, 1995(2), 455-466. TRYGGVASSON, E. (1973): Seismicity, earthquake swarms, and plate boundaries in the Iceland region, Bull. Seism. Soc. Am., 63, 1327-1348. VENTURA, G., G. VILARDO, G. MILANO and N.A. PINO (1999): Relationships among crustal structure, volcan- ism and strike-slip tectonics in the Lipari-Vulcano Vol- canic Complex (Aeolian Islands, southern Tyrrhenian Sea, Italy), Phys. Earth Planet. Int., 116, 31-52. WALTER, T.R. and F. AMELUNG (2004): Influence of vol- canic activity at Mauna Loa, Hawaii, on earthquake oc- currence in the Kaoiki Seismic Zone, Geophys. Res. Lett., 31, L07622, doi:10.1029/2003GL019131. WALTER, T.R. and F. AMELUNG (2006): Volcano-earthquake interaction at Mauna Loa volcano, Hawaii, J. Geophys. Res., 111, B05204, doi: 10.1029/2005JB003861. WALTER, T.R. and F. AMELUNG (2007), Volcanic eruptions following M≥9 megathrust earthquakes: implications for the Sumatra-Andaman volcanoes, Geology, 35, 539-542. WALTER, T.R., V. ACOCELLA, M. NERI and F. AMELUNG (2005), Feedback processes between magmatic events and flank movement at Mount Etna (Italy) during the 2002–2003 eruption, J. Geophys. Res., 110, B10205, doi: 10.1029/2005JB003688. WALTER, T.R., R. WANG, M. ZIMMER, H. GROSSER, B. LÜHR and A. RATDOMOPURBO (2007), Volcanic activity influ- enced by tectonic earthquakes: static and dynamic stress triggering at Mt. Merapi, Geophys. Res. Lett., 34, L05304, doi: 10.1029/2006GL028710. (received February 11, 2008; accepted June 12, 2008) Miscellanea 9-03-2009 14:42 Pagina 725