AMQ SN 1 Falcucci pub Available online http://amq.aiqua.it ISSN (print): 2279-7327, ISSN (online): 2279-7335 Alpine and Mediterranean Quaternary, 27 (1), 2014, iii - viii REPORT ON THE 2014 AIQUA SUMMER SCHOOL “LA GEOLOGIA DEL QUATERNARIO APPLICATA ALLO STUDIO DELLE FAGLIE ATTIVE: DAI TERREMOTI ALLA MICROZONAZIONE SISMICA” Emanuela Falcucci, Stefano Gori, and the 2014 AIQUA Summer School participants * Istituto Nazionale di Geofisica e Vulcanologia, L’Aquila Corresponding author: E. Falcucci ABSTRACT: We here summarise the activities carried out during the 2014 AIQUA Summer School, held from the 29th of September to the 3rd of October at Istituto Nazionale di Geofisica e Vulcanologia (INGV) of L’Aquila, and supported by INGV-Progetto Abruzzo. The school aimed at highlighting the major contribution of Quaternary geological investigation to the analysis of active and capable faults: this approach involves seismotectonic analysis and surface faulting hazard assessment on faults and deep seated gravitational slope defor- mations. The participants attended two days of classes, related to those topics, held by experts, and actively and largely joined the dis- cussions raised during the lessons; furthermore, they took part to a three-day fieldtrip in the 2009 L’Aquila earthquake area and sur- roundings. Concepts and methods learned during the lessons were applied to selected case studies: these included the 2009 L’Aquila earthquake causative fault and other major active normal faults affecting the Gran Sasso Range and the middle Aterno river valley. Moreover, participants actively took part in still ongoing paleoseismological investigations that aimed at the reconstruction of the recent kinematic behaviour and slip history of the Assergi fault, a major active normal fault of the central Apennines. Keywords: Quaternary geology, active and capable faulting, deep seated gravitational slope deformation, paleoseismology, surface faulting hazard, seismic microzonation. Active and capable faults and large scale gravita- tional slope deformations represent geological criticali- ties that, as elements of surface fragility, can interfere with human development; they must therefore be taken into consideration for seismotectonic analysis and, con- sequently, for a proper land use planning. These topics were discussed during the 2014 AIQUA summer school concerning, in particular, investigation methodologies and hazard assessment. The school took place in the Abruzzi region, at the Istituto Nazionale di Geofisica e Vulcanologia in L’Aqui- la, from the 29th of September to the 3rd of October. An appreciable number of “students” attended the event: undergraduates and Ph.D. students, postdoctoral fel- lows, researchers and freelance geologists, from central and southern Italy, and one coming from Great Britain. During the first two days, lessons were held by ex- perts in active tectonics, Quaternary geology, paleoseis- mology, neotectonics, earthquake geology, seismic microzonation. They lectured with laudable enthusiasm (and without remuneration!). They held high-value clas- ses and stimulated discussion among the participants on the different topics mentioned above, some of which are presently a matter of debate in the scientific commu- nity, especially with regard to surface faulting hazard assessment. The speakers thoroughly emphasised the importance of “old-school” geological survey, which lays the foundation for a multi-methodological approach in active and capable faulting analyses. We warmly thank all the lecturers for their irreplacea- ble contribution to the success of the school! MONDAY, SEPTEMBER 29 The first day of the school was opened by Dr. An- drea Sposato who, as a senior member of AIQUA, spoke on behalf of AIQUA itself, thanking all of the par- ticipants and lecturers for taking part to the summer school; he emphasised the importance of such events in increasing the awareness of the fundamental role of Quaternary geology in active tectonics analysis, espe- cially as for young scientists and students. Then, the INGV-Progetto Abruzzo was presented by its scientific coordinator Dr. Gianluca Valensise who, together with INGV-L’Aquila branch manager, Dr. Fabrizio Galadini, supported the AIQUA event. After these introductive talks, a series of scientific classes began with Dr. Paolo Messina, who illustrated general aspects of Quaternary geological investigations and their contribution to the reconstruction of tectonic and paleoenvironmental history of the central Apen- nines. Dr. Fabrizio Galadini gave a lecture on the role of Quaternary geological investigations on active and ca- pable faulting studies; his lesson was also dedicated to the definition of time intervals to assess the notion of “active and capable faults” for engineering practices in * Domenico Berti, Fabrizio Brutto, Tamara Carducci, Antonio Cefalì, Edi Chiarini, Silvia Crosetto, Fabrizio Cultrera, Paolo Di Marcantonio, Federica Durante, Pasquale Evangelista, Giandomenico Fubelli, Biagio Giaccio, Michele Lancia, Francesca Liberi, Lorenzo Lo Sardo, Serena Madonna, Gianmarco Mondati, Marco Moro, Giuseppe Napoli, Francesco Pavano, Michele Saroli, Stefania Silvestri, Andrea Sposato, Fabrizio Tinelli, Domenico Trotta Italy. Dr. Daniela Pantosti focused on general and meth- odological aspects of paleoseismological analysis, showing several case studies all over the world, and highlighting the effectiveness of such investigations for seismic hazard assessment. Dr. Gianluca Valensise illustrated the Italian Data- base of Individual Seismogenic Sources (DISS); he also showed some examples of peculiar geological features that mimic active faulting, and other cases where the relation between active faults at surface and seismogenic structures at depth can be complicated by the inheritance of older tectonic structures. Ing. Maria Basi explained the role and task of the Abruzzi Region local government in the seismic micro- zonation studies of the whole region (Fig. 1a). Dr. Paolo Boncio gave a lecture on the criteria to define zones of surface fault-rupture hazard; he illustrat- ed the new guidelines – currently underway – for sur- face fault rupture zonation in Italy that are still a matter of interest and debate within the Italian scientific com- munity and the Italian governmental institutions. Dr. Paolo Galli illustrated the state of the art of pale- oseismological investigations in Italy, showing some recent examples of such analyses along Italian major active normal faults. Dr. Alberto Pizzi showed the most recent outcomes of ongoing seismic microzonation studies of the town of Facucci E. & Gori S. iv Fig. 1 - Lessons held during the first two days of the summer school; a) Ing. Maria Basi illustrates microzonation studies presently ongo- ing in the Abruzzi region, b) Dr. Marco Moro shows the re-activation of large scale gravitational slope deformation during the 1997 Colfi- orito earthquake. Fig. 2 - Fieldtrip – Visit to the paleoseismological trenches dug across the Assergi fault. v Report on the 2014 AIQUA Summer School Fig. 3 - Fieldtrip – Moments of the lunch at Campo Imperatore, waiting for “arrosticini” to be cooked. Fig. 4 - Fieldtrip – The group discusses on the Campo Imperatore active fault strands. Mt. Brancastello in background, through the clouds. Sulmona, in the Abruzzi region: he outlined the geologi- cal factors that influence local seismic response and the issue of active and capable faulting affecting the Sulmo- na territory. TUESDAY, SEPTEMBER 30 The second day of lessons began with Dr. Marco Tallini, who illustrated the results of seismic microzona- tion studies carried out in L’Aquila after April, 2009, in the difficult post-earthquake framework; he examined all of the geological complexities needed to be understood and unraveled. Dr. Nicola Tullo showed the role of freelance geolo- gists in the ongoing seismic microzonation studies in the Abruzzi region. Dr. Marco Moro gave two lectures: the former about general aspects of deep seated gravitational slope movements and their relation with active tectonics; the latter focused on the use of satellite radar interferometry and paleoseismological techniques to investigate the kinematic behaviour and mechanics of large scale gravi- tational mass movements. He showed different case studies of large scale mass wasting that had been re- activated during large magnitude seismic events oc- curred in Italy during the past decades (among which the 2009 L’Aquila earthquake) (Fig. 1b). Dr. Stefano Gori illustrated, through case studies selected over the central Apennines, the role of Quater- nary geological field analysis in demonstrating the inac- tivity of tectonic structures despite the presence of mis- leading morphological hints suggesting activity. The last talks introduced the fieldtrips: Dr. Biagio Giaccio reported a comprehensive picture of the Quaternary geological evolution of the Paganica village area where, the activation of the normal fault causative of the 2009 earthquake caused surface fault rupture. Dr. Emanuela Falcucci illustrated the Quaternary geological evolution of the middle Aterno river valley and of the Subequana valley, and their relation with the long term kinematic evolution of the active normal faults that affect the eastern borders of these intermontane depressions. Dr. Stefano Gori and Dr. Marco Moro illustrated the present knowledge about the activity of the Assergi- Campo Imperatore fault system, where paleoseismolog- ical trenches, shown during the first day of the fieldtrips, have been dug. They also showed the structural and tectonic complexities that characterise the south- western flank of the Gran Sasso Range, resulting from the interference between active extensional faults and inactive thrust faults inherited by the presently inactive compressive regime. WEDNESDAY, OCTOBER 1 On the first day, the fieldtrip was spent along the Assergi active normal fault. Two paleoseismological trenches dug across the central part of the fault – made ad-hoc for the summer school – were visited. The walls of the excavations were observed, analysing evidence of the recent fault movements and searching for ele- ments that give information about its slip history (Fig. 2). We moved, then, to the Fossa di Paganica tectonic depression, located along the southern portion of the Assergi fault. Here, geomorphological evidence of the recent activity of the tectonic structures was analysed in the light of the results coming from paleoseismological investigations, which were recently performed along this part of the fault (Moro et al., in prep.). After a wonderful and pleasant lunch, where the participants experienced and made practice in the art of cooking “arrosticini” (accompanied by more than one glass of red wine!!) (Fig. 3), the fieldtrip continued in Campo Imperatore highland, specifically focusing on glacial and peri-glacial deposits exposed along the plain and on the active normal faults pattern that affects the area (Fig. 4). During the last part of the afternoon, some of the closed tectonic depressions that characterise the south- western flank of the Gran Sasso Range were visited, with a particular focus on the bounding fault scarps; the evidence of recent activity of these structures was dis- cussed, together with their tectonic “significance” in the complex structural framework of the mountain front. Furthermore, geomorphic evidence of the occurrence of large scale gravitational slope deformation along the Gran Sasso southwestern flank was shown. THURSDAY, OCTOBER 2 The first half of the fieldtrip on the second day was led along the Paganica fault, whose activation deter- mined the April 6, 2009 seismic event. In particular, the vi Fig. 5 - Fieldtrip – Dr. Biagio Giaccio describes Middle Pleistocene tephra layers contained in alluvial sediments displaced by the Pagan- ica fault. Facucci E. & Gori S. site of the water main that had been damaged by the fault activation was visited, analysing the Quaternary (and Late Pleistocene-Holocene) deposits displaced by some secondary fault planes exposed along the main fault scarp, in the area of Paganica. Evidence of activa- tion of the Paganica fault during seismic events preced- ing the 2009 one was examined. Alluvial fan and fluvial deposits containing Middle Pleistocene tephra layers and displaced along the fault were analysed in detail (Fig. 5). During the afternoon, a fault plane exposed at the southern termination of the Paganica fault, in Poggio Picenze, was observed, described and analysed; the structure brings into contact lacustrine and alluvial deposits. Then, evidence for the late Quaternary activity of one of the northernmost segments of the Middle Aterno Valley fault was illustrated near Cor- bellino: fluvial-lacustrine deposits are affected by a complex shear zone, synthetic to the main fault scarp; as a consequence of the fault movement, they were placed in contact with slope deposits. The day ended with beers, teas, juices, snacks and laughters in San Demetrio ne’ Vestini. FRIDAY, OCTOBER 3 The last fieldtrip focused on the Middle Aterno Valley-Subequana Valley fault system. The partici- pants enjoyed a wonderful panoramic view of the scarp of the Roccapreturo fault segment from the village of Goriano Valli (Fig. 6). The Roccapreturo fault scarp is one of the most impressive fault scarplets of the central Apennines. Evidence for the Quaternary and Late Pleistocene- Holocene activity of the Roccapreturo segment was illustrated and described in more detail in the village of Roccapreturo: there, the tectonic structure brought in to contact the carbonate bedrock, cropping out on the footwall, with Late Pleistocene-Holocene deposits, ex- posed at the base of the fault scarp. The stop was followed by the description of the Qua- ternary morpho-stratigraphic and tectonic evolution of the Subequana valley. In particular, some fault planes related to the Subequana valley fault were shown in the vii Report on the 2014 AIQUA Summer School Fig. 6 - Fieldtrip – Dr. Emanuela Falcucci describes the Middle Aterno Valley fault system. Fig. 7 - Fieldtrip – Dr. Giandomenico Fubelli describes one of the active fault plane that crosses Castelvecchio Subequo. area of Castelvecchio Subequo (Fig. 7). Evidence of the displacement of Middle Pleistocene fluvial deposits and of Late Pleistocene slope sediments along these faults were analysed in detail. The organisers Emanuela Falcucci and Stefano Gori warmly thank all the participants for the days spent to- gether and for the more than pleasant company! Every- one was extremely friendly, active and interested, and the mood was always overjoyed and superb!! The or- ganisers consider the summer school experience as extremely positive, a cultural and human growth, and they hope this will not be the last “stop” but the first of many other similar initiatives !! viii Facucci E. & Gori S. Ms. received: October 26, 2014 Final text received: November 16, 2014 ix