Engineering GcopltY8ics - A New Conccpt A. E. SCHEIDF.GGEH * SU)DIARL In :lll:ll\) g~' to "('ugi n(ll'l'ing j,h,y sil·II". "cn"in c(, l'iul{ gco· ph ,'"I>ÌC's" is ,]('fiued a!! th c cli gi lll'e l'ing uppli('atious of gpophysir:l l plu;: uo!llcua. 'l'hl 's(J Ìue!m](' ]ll'(){'rS SCS uCC' U1'l'ing all,vwhrl'r il'O!ll t lH' F.nrth's ('01'(\ to the Il]l]l rr at!llo~pll('rr: tlm s, thPl\i i ~ \I va!!t l'angc oi pO~lIihl., :l}lp JÌC'n tiol)s. lu th i ~ pllpcr a lliS('lls sioll i~ j:h'cll (Ii cngint'cri nl-( a l' plinl tin l1 8 (l I Ow pllJ~ Ì ('~ ot Ihe s o li,I J:a r th (i lwl wH 1\jl S(,is lllll]ng~", "o!t-:ulfll ngy 11114 \ gC"lIu'('}la u il'S), ,, ' 111(, I.II)'8i('s 01 tJlI~ h y ,l r,u'l'lwrtl (i n f llltlin g hJtl ml()~.\· ) aI .. 1 (.1 Il,.' l,h.\"Il il'8 (l I Il, c a lll >osJ.h cm (i I1 I'1Ulli ll;; Inl'nll ,l oCII rlmlligh l n ing), 1~ ' '''SSUK I:0 , - Anll ]ogtHl1énto a l tCl'lII iUé "1I6i(':\ illgeJ.tucrislicn", "gcn fl llil~a ingrgnCl'Ì sticu " ~i d ('fl n i~ ('C CO III(' ap!,!il' l\ zinn c all' ingcgllc l' Ìn ,li fe n n!!\cni gc ofisici. Qucsti l'OIll]u', 'nll nn o Ì 1'I'o('('ssi l'llti ,n"n'ng(lI\o in Illl 'l11a- lUlil]U C j,unto tlalnudllO Il ell .\ '1' en ll all'altn al'lIIollfl'nl.; Ili lin i l'enor Jllc ('a!lljJO I] i i''' s!;il) Ìli al'plÌl'azinni. In '1 \1eal(l 1[1\'01'0 "ieue fatta unii ,!i s('u8sio llt: sull'ap. pl il'l\zi ouli all'ingl'gn cri,\ ,Iella fil>i<'n ,Iella Terra ~nlilla (<'O!!\IH' elHl en tc sisJII(I- logia \· ulcnnn logia c gCU !llc('culli (' u), lid i" fisil'a tlel l'i ,iL'( I ~ fCi'[I (indudcllIlo J'iol rn l"g ia ) e infine .Iell a l:I~i l'a Ii llJ\' a t mlll,f" )'a (in l'hlt\l! nt e i h.rum ] .. c i Inl- mi .. i). 1. - l'XT1WDUC'TIO!'i". If ono tr a mlates tllO wOl'd Ugeophysies" from Ol'(!tl k inliu Bngli.~h) it signilies Uthe na.ture (lf th o Eal'th". Meant is (lf e(H\rse the ,~tUlly of the nature of thc Eal' th. In the motlerll conno ro t io n, the \l'(ml Uphysi es" ,1oc,'1 not mc... .. n " na ture" in gt'>uel'al ali)" more, huì- t he work- i ll gs o [ t he ma·tcri als in v ol ved oxc hulin g changcs i n compos itio ll . • T cc hn ilw hc Hod, sc lml e \Yil~n , Jw;IÌl ut flil' (: l'O JlII ~'si ]i A - I O~jl \rien Kl\rl!;],lat z 13, Au st r ia, .-\. l: .. ~CHEIDEGGF.]( By its (1l'jinition, "geophy~i(ls" iH therefore the ~t.ndy of the physies of the Ii:al't.h. C'ommonly, thi~ inelndes no\\' the gamut fnnll t.he Eart.h's (10m lo tlw f!OlaT-telTestriaI l'elat.ionship~. App!itèatùm8 of geophysies to the economie fiehl have, t.hlls far, mostly been COldìlWd to geophysiea.l explomtion. It is dpar, llO\\'cver, that the~e applieations could be Vll-~tJy extend('d, ina~mneh as many aS}Jeet-s of gcophysies Iend them- flcl"es 1.0 engineering nses. Tn a,ualo!!y with "engineering }Jhysies", I like t.o (Iesignat", the systematie flhHly of engineering applieatiom of geophysks as "engiucering g'co}Jhysie.,;". Some pngineerini{ applica- tiOUfl of gPollh.\·flies are, of eonl'~e, weII known, ~ueh as engineering seis- mology, bnt on t.he whoIe, geophy~ie~ ha~ not. as sy~tenlll.til'aIIy hecu ap}Jlied to engiueeriu!! a~ it might. have been. Tn this Impcr, I only }Jlan to diseuss some of t.he engiueerini{ all- IIIit'atiom of geo}Jhysie.,; tha.t might 1m usdul in pra.et.ieal \\'ork. 'l'o give a eomprehemiye revip\\, WOIÙ(! be (luitc impossible as t.he subjeet is vaflt" 'l'hl' physies of thc Eart.h is eonuTlotdy di"ide(! into the Ilhysies of t.he solid earth, the IlhyHic~ of the hy(lrosphere a,tHl the phy~ks of t.he atmosphere. I n \\'hat foUol\'s, r wiII keep t,]w sanI(' (!i"ision. ~_ - K:\GI"XEERT:\G GEOPIlYSICS OI' 'l'IlE SOLID EAR'rIl Fol' man, t.he ~Ill'faee of the solid parth is Ilrohably t.he ITlOSt. im- portant l'l'giOII of the rnivel'f!c becanse hl' !ives thereon. fn t.his ponneetion, the fast or sIol\' ehanges of t.his surfa,ee are of pa'l'tienJa.l' signilil'anee, ~inee the:.- re}Jre~ent. a,n alteratiou in hi,~ habitat, These ('haltg'es are gcncrally ('ause(! by "gl'O"-llltysieaI pro('Psses I\'ithin an(! wi!hont. the Ii:arth. Pl!,~l ('hHng{',~ l'an oeeul' a~ veritable ea.ta~tl'ophe~, SIow ehanges, 110\\'evel', ean be jll~t. lUI serious althollgh thcy may l:wk the IlllTtieularly spee.ta,enJa.l' a~pect.s of a wddenly oeeulTing disaster. If (1)(' thinkfl of (lisasters, some of t.he most. feal'ed ones a,l'e earth- qnake~, Ii:art.hquake~ are flhoeks that. muaIIy oecllI' without waming; they l'u!!ClHlel' sndden disphwement." 011 the Earth's sllrfaee that. ea.n eanse bnildiugs to {'ollap~e_ The stndy of eal'th(IUakes is ealletl "seis- HJologY"j "engineering seisnlOlogy" is 0l!P of t.he few hm,nehes of l'n - i{ineering geophysies \\'hieh has all'eatly reeei"ed sonw at.t.ention. Thus far, I\'hat. t.rigg(\l's an e:wtltquake is nut knol\'n, lt 1m .. ,; bepll fonntl that ENGI S EERl )o:G GEQ PIIY S I CS - A SE\\" CQ~C~; I'T carthqllakeli du )\t.er Slllldll ll y in ccrblin rcgiun li (n ot.'\bly thc l'il't'lIm- .P~I{'i!1c belt) , bllt. whnt act.\1l1lJ~- l'amc~ an cal'thql\ake t.o OC('l!r, is not kllo\\"n. Thus, thc gelHwallSoismk l'iHk l'an be tlet ermino ll fol' a (·t;lt.ain area, but a pl'edicti(m of ellrthqllake~ has no1. ~'ct h(~e l1 n('llieved. In- ('.itlolltally, thi~ is a rathcl' "hotl! ~Ilbject jmt. no\\". 1;:art.hquakes are gco.- l.rll a mi ('. phenomen:io; i.c. Il lI1'IIOlllOJ!ll baHicall~' call!)!!l l by J)]'o('{' s~es tnkinJ,! plaee in t.hc Eal't.h's interi!)!'. Of a similal' oriJriu :11'0 volcanic erlll't. ioIl S. Sudi el'uptioll ;; 1I:\\'c \'; 111 1$(\\1 sl)c('tm' IJlar d hi:Ui tce l'~ in hi6torìcnl timeli; one neCiI onl~' I.hink or t.he diHa.~t.c .. S ai. He l'CII LIIlCIIIII amI P ompe ii ,\1111 (I{ Ml.. Pell'e. Tbu l'\ , llI:ion y (·olllll.ri eli ('ollid makc gootl engillccrin~ Ulie o[ gt'Ol)h~'sieal ohsen'al.i olls on yolcanocs iLnd fl'Om an Ilntlerlitnnding' t)f thei .. nU'('IlH-ni~lll. Of dircet apIllieability tu t!1lgineering are geOlJh ysicnl events oc- NIl'ing quitegencmlly on "~I(llJes ". I mean any kill11 or 1I1I1p~lj: ex('ayat,- i(lJ1 Ij, motLntain si.-Ies, embanklllt'nts etc. Qllestiom o[ tlt e litability (If MIC.h slopcs haYI' hOe.11 stlld ie ll l'xl.enslvel.Y by ciyil 01l ~ilH'('.1'8: t.lte $!"co}lhysieist , howevcr, wii'lh\!s hl go hll'tIlCl', ina~mtLclt lIS tllo entil't'. p hys ics or tlw mo t ioll, illdwlill~ the ]>1Iysicli or t1l c VI!I): l'o ll a,p!ie, is or intce l"Q!it to{) hi.m. Contral'iwise, thc (·II /..>1l1oor ili lIot {'Olleerncti \\"illt t.Iw la t,l.cr, bc(~ausc his I1Hli li a im is to prevfll t IIIICI! a li OC('(ln "Q I\('('" NevI··r- t. hclc~s, t hc mCehallil'k nf I~ la·lllllSlide, if known, {'nulll alMI be Imt tn engineerin g me, e.g. [or th o e",' lIlllation of t·lle safety (Il n site or in t.he Lle~ign of Ill'oteetive mOllsuros. Stahility cf;timah!~ on ~ IOIJCS oftcn de pOlltl on a kJl()\\'lell~o lIf the physics of a Ilotential ~ lid e. Stran~dy e uough, t.hc physics or a m,lj(l[' ~lido is stili largely a Ill!l tLN (Il spe('ul- nti(lil. The oTllillal'~- fri(,t,ioll hct\\"ccn t.1w J'(wks is sim pl.\" too gl'cat. fOl" li IlmjOl' sl itl c to O(:C UT i~t l\1 1. One sta·mls h el'c be[ol'e Il g l'ca t ll u:nlt! . F:HHuU S cases a re tlte s1 ideli al. Pmnk, AI1J{'rl.~l in 1903 :lIul th e IIlil1 e at V.ljont in UI)IICL' lLa l ~' in l !)(i;i. T!t(, 1111.1.1' " \HUl li fla .. l.icu liU· I~' d isas troll )\ e ven t .. A tlam \\"aing mot.lon !u·C'('Jcmtell eventually t u :W celltilllt. Thus Iar, onIy statist,ica.J prognosticat,iom can be mallc. One tn'ats the "hYllrogravh", that is the t-emvoraI,~pquenee of wat.er leyel readings, a.s a "timI' seric~". 'fhe flt,atistiell.1 lll'operties oi sueh time series can be analyse(l ailil describell. From thi.~, prel1ictiollS of the generaI frequency of the oeeurrence of a jm-rtieular size tlooll, if not the time thereof, can he maile. Less spectaculil'l', but of great importa.nee, is the meehanic~ of erosion: the near-shore circula,tion ~~-stem on a coa~t, is resvollsible ior the evolut,iou oi beaches ek., meaJl(lpl'S create river termees, and gllllying the IIegra.IIation oI a sIOI)('. Glaeiers are also vart oi the hYIIrosvhere. For engineering IHu'- l)oses, they haye reeently gaineUy COl]('(',]'IH'11 wit,h wind stress. The willil stress ean 1m substa.ntiaI, a.s is eviilenced by t,hl' Ilefltructioll eause(l by torua