3d Physics-Based Earthquake Scenarios in Istanbul for Seismic Risk Assessment


Abstract eng:
In the framew work of a reseearch cooperaation between Politecnico ddi Milano, Itally, and Municch Re, Germanny, 3D physiccsbased numeriical simulationns are carried out, considerring possible rrealizations off a future earthhquake of maagnitude ranginng from 7 to 7.44 along the Noorth Anatoliann fault segmennt facing Istanbbul across thee Marmara Seaa. Simulationss are carried out o using the speectral elementt code SPEED D (http://speedd.mox.polimi.iit), after consttruction of a nnumerical messh consisting of 2.257.482 hexahedral elem ments of spectrral degree 4, ending e up witth a total of 475.048.329 deegrees of freeddom, to coverr a t huge dimeensions of thee numerical m model, simulattions were carrried out on thhe frequency rannge up to 1.5 Hz. Due to the in supercomputeer facilities avvailable at CIN NECA, Italy ((www.cineca.it), up to a tootal of about 50 5 scenarios, differentiated d terms of earthhquake magniitude and the kinematic k slipp distribution. The geologicaal setup was constructed c baased on differeent seismic microozonation andd site characterrization studies available in Istanbul. Numerical reesults were obttained in term ms of broadbannd ground shaaking maps (0--25 Hz), referrring to a regioon including thhe wide urban aarea of Istanbuul and surrounndings, for a total horizontaal extension off the model off 165 x 100 kkm2, down to 330 km depth. A novel approoach to constrruct broadband accelerograams was devissed, consistinng of the folloowing steps: 1) training of ann artificial neuural network (A ANN) to correelate the simullated long perriod spectral oordinates with the short periood ones, using a digital stronng motion reccords databasse; 2) applicattion of the A ANN to estimate the short period spectrral ordinates, based on the lonng period results of the nuumerical simuulations; 3) appplication of an a iterative freequency scalinng procedure, wiith no phase cchange, for thee simulated acccelerograms too match the brroadband response spectra. The effects oof different faault slip modeels and earthqquake magnittude are testedd, in order too identify the contribution to seismic hazarrd of differentt earthquake sscenarios, as a function of the position oof the rupturedd segment aloong the fault, as well as the onnset of possiblle forward dirrectivity condiitions. These nnumerical eartthquake scenaarios are the baasis to construuct an enhanced probabilistic/ddeterministic approach to seeismic hazardd assessment, iillustrated in a companion paper p submitted to the 16WCE EE conferencee (Stupazzini eet al., “PSHAee (Probabilistic Seismic Hazzard enhancedd): the case of Istanbul”).

Contributors:
Conference Title:
Conference Title:
16th World Conference on Earthquake Engineering
Conference Venue:
Santiago (CL)
Conference Dates:
2017-01-09 / 2017-01-13
Rights:
Text je chráněný podle autorského zákona č. 121/2000 Sb.



Record appears in:



 Record created 2017-01-18, last modified 2017-01-18


Original version of the author's contribution as presented on USB, paper 1478.:
Download fulltext
PDF

Rate this document:

Rate this document:
1
2
3
 
(Not yet reviewed)