SOURCE MODEL OF THE 2010 ELAZIG KOVANCILAR EARTHQUAKE (M w 6.1) FOR BROADBAND GROUND MOTION SIMULATION

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1 SOURCE MODEL OF THE 200 ELAZIG KOVANCILAR EARTHQUAKE (M w 6.) FOR BROADBAND GROUND MOTION SIMULATION Mehmet Baykal MEE0509 Supevis: Hie Miyake ABSTRACT On 8 Mach 200, an eathquake f M w =6. ccued in Elazig and Kvancila in Tukey. This event is knwn as the 200 Elazig Kvancila eathquake. It caused massive destuctin in the ual aeas affected and claimed lives. We pefmed the empiical Geen's functin methd t simulate the stng gund mtin f this event and the lagest afteshck ecded with magnitude M w =5.5, utilizing stng gund mtin data fm stng mtin and badband velcity statins. We then cnveted these ecds int a unifm sampling fequency t cay ut the simulatin. Amplitude spectal analysis was used t find an estimatin f paametes used in the empiical Geen s functin methd. The fcal mechanism detemined by Tan et al. (20) was used f the simulatin f the mainshck and the lagest afteshck. The best suce mdel was estimated by fitting the synthetic acceleatin, velcity and displacement t the bseved seismgams. The btained size f the estimated stng gund mtin geneatin aea was calculated as 2.80 km in length by 2.00 km in width f bth the mainshck and the afteshck. The uptue stating pint was fund t be at ntheast and suthwest f the estimated stng gund mtin aea f the mainshck and the lagest afteshck, espectively. We detemined the scaling paamete f the mainshck as 2 and the stess dp cectin fact is 3.5. The detemined scaling paamete f the lagest afteshck is 2 and the stess dp cectin fact is 2.5. The abve analyses suggest that the stess dp cectin fact f the stng mtin geneatin aea f the mainshck is.4 times highe than that f the lagest afteshck. The 200 Elazig Kvancila eathquake is chaacteized by shallw depth uptue with high stess dp. This fact is cnsideed t be ne f the suce effects t geneate sevee gund mtin f the damaging eathquake. Keywds: Elazig Kvancila eathquake, empiical Geen s functin methd, stng mtin geneatin aea.. INTRODUCTION The 200 Elazig Kvancila eathquake (M w =6.) at 02:32:30 (GMT) n 8 Mach, 200 ccued at the east pat f the East Anatlian Fault Zne (EAFZ) in Tukey. The shaking was felt aund Elazig, Bingl, Tunceli, Mus, Diyabaki, and Ezuum cities. The eathquake caused 42 death, 37 injued, 695 heavily destyed huses, and 978 patially destyed huses aund Elazig and Bingl cities based n ept f Disaste and Emegency Management Pesidency f Tukey (DEMP). Disaste and Emegency Management Pesidency, Tukey. Eathquake Reseach Institute, Univesity f Tky, Japan.

2 Eathquake Depatment at DEMP epted the magnitude f this eathquake as M L =5.8 and M w =6.0, its epicental cdinates as N, E which was lcated in Elazig city in Kvancila pefectue and with depth f abut 5 km. Accding t the Centid Mment Tens slutin f the Glbal GMT Pject, this eathquake has a cmpessinal axis n the stike f 228, dip with 83 and ake angle f -2. The distibutin f the afteshcks indicates that the main fault shuld be abut km lng and 2 5 km wide (Figue ). On the same day, anthe eathquake ccued at 07:47 (GMT) and the Eathquake Depatment epted the epicente cdinates f the secnd eathquake as N, E which was lcated in Elazig Palu, and its magnitude as M L =5.6 and the depth f 5 km. Accding t the Centid Mment Tens slutin f the Glbal CMT Pject, this eathquake had a cmpessinal axis n the stike f 23, dip with 78, and ake angle f -. Figue. Lcatin f the Klazig-Kvancila eathquake is dented by the black sta, the ed and geen dts ae the afteshcks. The yellw tiangles ae the seismic statins. Accding t the ecent develpments based n wavefm invesin f stng gund mtin data f estimating the uptue pcess duing lage eathquakes, stng gund mtin is elated t the slip hetegeneity athe than the aveage slip ve the entie uptue aea as studied by Iikua and Miyake (20).The stng gund mtins at specific sites nea the fault can be estimated by using the empiical Geen s functin technique. In de t calculate nnlinea dynamic analysis f stuctues which ae needed t design eathquake-esistant buildings, bidges and nuclea pwe plant, this kind f techniques ae used effectively. In additin, mst stng mtin pedictins in eathquake hazad analyses have been made by using empiical attenuatin-distance cuves f peak gund acceleatin (PGA), peak gund velcity (PGV), and espnse specta. This infmatin is defined nly by magnitude and fault gemety. Hweve, gund mtins which caused damage ae smetimes chaacteized by uptue diectivity pulses like the 995 Kbe and the 999 Izmit eathquakes. 2. DATA In this study, we used acceleatin data that ae ecded by Natinal Stng Gund Mtin Netwk (NSGMON) being peated and maintained by the Disaste and Emegency Management Pesidency (DEMP), a gvenmental agency in Tukey. We als used velcity data ecded by Kandilli Obsevatin and Eathquake Reseach Institute (KOERI) managed by Bgazici Univesity We selected tw events. The fist ne is the mainshck f the 200 Elazig Kvancila Eathquake (M w =6.) and the the ne is the lagest afteshck (M w =5.5. In additin, we selected anthe afteshck in de t use as an element eathquake (M w =4.8) in empiical Geen s functin methd by Tan et al. (20). We used fu acceleatin data f the mainshck which wee etieved fm the statins neaest t the mainshck; these statins ae BNG, DYR, ERC, and PAL. The Figue 2. Epicental lcatin f the mainshck, lagest afteshck and lcatin f the statins. 2

3 ecds fm the badband velcity statins wee nt utilized since these ecds wee clipped and f this easn ERZN and DYBB ecds f the mainshck cannt be used f the cmputatin f the EGFM. As f the lagest afteshck, the data used wee fm ecds f the statins BNG, PAL and DYBB. F the element eathquake, ecds fm BNG, PAL and ERC statins wee used. Figue 2 shws the statin distibutin.. 3. THEORY AND METHODOLOGY One f the mst effective methds f simulating stng gund mtin that cmes fm a lage eathquake is t use bseved ecds fm small eathquakes ccuing aund the suce aea f a lage eathquake. Actual gelgical stuctue fm a suce t a site is geneally me cmplex than that assumed in theetical mdels. Actual gund mtin is cmplicated as well nt nly by efactin and eflectin due t laye intefaces and gund suface but als by scatteing and attenuatin due t lateal hetegeneities and inelastic ppeties in the ppagatin path. Hweve, main appach f this pupse is t estimate stng gund mtin f a lage eathquake using the ecds f small eathquakes which ae cnsideed as an empiical Geen s functin (EGF) by Iikua (986) and anthe study by Iikua and Kamae (994). The empiical Geen s functin methd takes in n tw scaling elatins between a lage and a small eathquake. They ae, a) scaling elatins f suce paametes, b) scaling elatins f suce specta. In the fist scaling elatins, fault paametes studied by Kanami and Andesn (975) ae expessed by the Eq(): L W T M () = = = = N, l w τ m whee L and l ae fault length, W and w ae fault width, T and τ ae slip duatin time, M and m ae seismic mment, and D and d ae fault slip f small and lage eathquakes, espectively. The scaling is based n the idea f size independent stess-dp. The secnd scaling elatins ae epesented by the ω -2 suce specta scaling mdel studied by Aki (967) and Bune (970). Then the spectal elatinship between lage and small events becmes Eq. (2) and (3) U u M A CN 3 = =, CN, m (2) = a whee, U, u, A and a ae flat levels f displacement specta and flat level f acceleatin specta f lage and small events espectively as shwn in Figue 3. (a) (b) The same figue shws the displacement and acceleatin suce specta f diffeent sized events pedicted by the ω -2 mdel. Whee U and u ae flat levels f displacement specta at lw fequencies, f cm and f ca ae cne fequencies and A and a ae the flat levels f acceleatin specta at high fequencies between the cne fequency and the cut-ff fequency 3. Fmulatin f the Simulatin 3 Figue 3. The schematic figues (a) displacement amplitude specta and (b) acceleatin amplitude specta. T pefm the simulatin f the stng gund mtin fm the lage event using the ecd f a small event as an empiical Geen s functin, pimaily the need t detemine the paametes f C and N (3) 3

4 which ae defined in elatins fm the Eq. (2) and (3): U ( t ) N N = i= j= F ( t t ) ( C u ( t )), (4) t = β + ξ V, (5) ( N ) n ' ( k ) T F ( t ) = ( t t ) + [ { }]. (6) δ δ t t ( ) k k= ( N ) n' n' ( ) ( N ) n ' e e Obseved ecd fm a small event is egaded as an empiical Geen s functin, and it is summed by fllwing Eq. (4) with time delay accding t the scaling law and fault aptue pcess. The fmulatin f the EGF methd by Iikua (983; 986) is based n the deteministic kinematic Figue 4. Schematic illustatins f the empiical Geen's functin methd (left f the figue) and filteing functin (ight f the figue) used in this study. ae the atis f the fault dimensins and stess dps between the lage and small events, espectively, and the * indicates cnvlutin. In the Eq. (6), F (t) is the filteing functin (cectin functin) t adjust the diffeence in the slip velcity time functins between the lage and the small events. β and V ae the S-wave velcity nea the suce aea and the uptue velcity n the fault plane, espectively. T is the ise time f the lage event, and defined as duatin f the filteing functin F (t). It cespnds t the duatin f slip time functin n sub fault fm the beginning t the time befe the tail stats. n is an apppiate intege t weaken atificial peidicity f n, and t adjust the inteval f the tick t be the sampling ate. 4. RESULTS AND DISCUSSION suce mdel. Gund mtin fm an eathquake can be expessed as a space-time cnvlutin f slip distibutin n the suce effect with ppagatin path effect. The suce effect f this mdel is chaacteized by five paametes in the Eq. (4) and (5): fault length (L and l), fault width (W and w), final ffset ( and ) (slip), ise time (t and t ) (slip duatin), and uptue velcity (V). U(t) is the simulated wavefm f the lage event, u(t) is the bseved wavefm wavefm f the small event, N and C F the lagest afteshck we detemined the value f C equaled t 2.5 and N equaled t 2, thus the pssible estimated stng gund mtin geneatin aea f the fault was 2 x 2 (Table ). F this, we Table. Calculated scale paametes N and stess dp cectin fact C values f the mainshck and the afteshck. Figue 5. Suce paametes f the mainshck and the lagest afteshck; the black dts epesent the uptue stating pints. f cm f ce (Hz) (Hz) C N Mainshck The lagest afteshck

5 pjected 4 cells f the afteshck and the uptue stating pint was best lcated at cell (2, 2) this was pven by the gd fit ageement f the bseved ecds and the synthesize mtin, which is shwn in Figue 5. Figues 6 and 7 cmpae the bseved wavefm and synthesized mtins. We cmpaed u esults t the scaling elatinship f stng mtin geneatin aea t seismic mment (Miyake et al., 2003). Ou analysis shws that the lagest afteshck lies n the same estimated stng gund mtin aea. Figue 6. Cmpaisn f bseved and synthetic wavefms f the mainshck. While the mainshck shws it geneated a elatively lage seismic mment in cmpaisn t the eathquakes shwn in the scaling f the stng mtin geneatin aea t seismic mment as shwn in Figue 8 (a). Additinally, Figue 8(b) shws the cmpaisn f u esults t the scaling elatinship f ise time and seismic mment. It suggests that the afteshck ccupies the same estimated stng gund mtin aea. On the the hand, the ise f the stng mtin geneatin aea f the mainshck was shte than the empiical scaling elatinship. Figue 7. Cmpaisn f bseved and synthetic wavefms f the lagest afteshck. Figue 8. The left gaph indicates the scaling between stng mtin geneatin aea and seismic mment. The ight gaph shws the scaling between ise time and seismic mment (Miyake et al. 2003). 5

6 The mainshck geneated seismic mment fm the smalle pat f the fault plane with a fcal depth f 5 km. This might be the easn f the massive destuctin caused by the 200 Elazig Kvancila eathquake. Anthe pssible easn why we btained a M6-class eathquake whee the absence f any seismic activity ecded in the egin. 5. CONCLUSIONS In this study, we simulated gund mtin f the mainshck (M w =6.) and that f the lagest afteshck (M w =5.5) f the 200 Elazig Kvancila eathquake using the empiical Geen s functin methd. F the simulatin, an afteshck with the magnitude M w =4.8 was selected as an element eathquake. We utilized the data fm fu acceleatin statins and tw badband velcity statin ecds. Using the fu stng mtin ecds at the fu statins, we calculated the suce paametes f the mainshck. The size f stng mtin geneatin aea f the mainshck is fund t be 2.8 km in length by 2.0 km in width with the uptue stating pint at the ntheast bttm f the estimated stng gund mtin geneatin aea with a depth 5 km and ppagated fm deep t suth-westwad with the velcity epesenting 80% f shea wave velcity. Then we cmpaed the bseved ecds and synthesized mtins between acceleatin, velcity, and displacement data. The cmpaisn has a gd ageement t all the statins used except f the ERC statin. We d nt have any infmatin abut sil cnditin aund the statin exactly. Hweve, Ezincan city is lcated nea the Fiat ive. S, the ERC statin might be influenced by sme effects f the nea suface sil. F this statin als, we pted t use ERZN velcity ecd as an element eathquake. The distance between these tw statins is appximately 30 km. We als simulated the lagest afteshck f the Elazig Kvancila eathquake using thee acceleatin ecds and badband velcity ecds. The size f the stng mtin geneatin aea f the lagest afteshck is detemined at 2.8 km in length by 2.0 km in width in which the uptue stating pint is at suthwest bttm pat f the estimated stng gund mtin geneatin aea twads the ntheast with a depth f 7 km. The estimated stng gund mtin geneatin aea is lcated suthwest f the mainshck and 4 km away fm its epicente. The abve analyses suggest that the stess dp cectin fact f the stng mtin geneatin aea f the mainshck is.4 times highe than that f the lagest afteshck. The 200 Elazig Kvancila eathquake is chaacteized by shallw depth uptue with high stess dp. This fact is cnsideed t be ne f the suce effects t geneate sevee gund mtin f the damaging eathquake. AKNOWLEDGEMENT I wuld like t expess my deepest gatitude t my advis D. Tshiaki Yki f giving me valuable advises and suggestins. REFERENCES Aki, K., 967, J. Gephys. Res., 72, Iikua, K., 986, Pc. 7th Japan Eathq. Eng. Symp., 5 56, Iikua, K. and Kamae, K., 994, Annali Di Gefisica, Vl. XXXVII, N6, Iikua, K. and Miyake H., 20, Pue and Applied Gephys., 68, Bune, J. N., 970, J. Gephys. Res., 75, Kanami, H. and Andesn, D., L., 975, Bull. Seism. Sc. Am., 65, Miyake, H., Iwata T., and Iikua K., 2003, Bull. Seism. Sc. Am., 93, Tan, O., Pabuccu Z., Tapidamaz M. C., Inan S., Egintav S., Eyidgan H., Aksy E., and Kuluztuk F., 20, Gephys. Res. Lett., 38, L304, di: 029/20GL