APPROPRIATE ATTENUATION MODEL FOR CHIANG MAI, THAILAND FROM FIELD MEASUREMENT TO MODEL EQUATION

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1 Geotec., Const. Mt. & Env., DOI: ISSN: (Print), (Online), Jpn APPROPRIATE ATTENUATION MODEL OR CHIANG MAI, THAILAND ROM IELD MEASUREMENT TO MODEL EQUATION *Twtchi Tnchiswt nd Nutpong Hirno Deprtment of Civil Engineering, culty of Engineering, Ching Mi University, Thilnd *Corresponding Author: Received: 25 Dec. 207, Revised: 5 Jn. 20, Accepted: 5 eb. 20 ABSTRACT: Erthquke occurs frequently in Thilnd especilly in upper norther prt in pst 5 yers go. Thilnd hs lso mny fult, especilly upper northern. The upper northern prt my risk by erthquke. The erthqukes dmge of buildings or people nd these dmges will depend on pek ground ccelertion (PGA). Pek ground ccelertion (PGA) is n importnt fctor for nlysis nd design of building or relted structure on top. This study ws nlyzed erthquke ttenution model of group Next Genertion Attenution Models (NGA) nd Stble Continentl Region. irst group, the model ws listed s Abrhmson nd Silv (200) nd Idriss (200). or the second group, the model ws listed s Toro et l. (997), Hwng nd Huo (997) nd Dhle et l. (995). Ech model nlysis ws done by using the erthquke intensity tht hd hppened ccording to the erthquke tht detected from field mesurement of 6.3 Richter scle on My 5th 204. The epicenter ws in Me Lo district, Ching Ri province in northern of Thilnd. The result of this reserch ws summrized by men of pek ground ccelertion (PGA) between the ttenution models nd the field dt mesurement by checking the ccurcy of ech model. It cn be concluded tht the ttenution model of Abrhmson nd Silv (200) give more ccurte ccelertion dt compre to other models. Keywords: Erthquke, Pek ground ccelertion (PGA), Attenution models. INTRODUCTION The upper northern of the country, most of Thilnd re chrcterized by mountins, is one of the cuses of the erthquke fult nd erthquke sttistics in countries, Thilnd often occur on the North. The erthquke occurred, cusing structurl dmge to buildings. The PGA (Pek Ground Accelertion) is vlue tht is importnt to the severity of the erthquke will be used to nlyze the ttenution, more distnce from the center of the erthquke, the PGA, it's even less. This pper is study for the pproprite ttenution models for Ching Mi, Thilnd re. This pper presents study of equtions for the pproprite of ttenution to Ching Mi. The erthquke in Me Lo, Ching Ri on My 5th 204 ws selected s reference of erthquke mgnitude recorded by field mesurement dt. The ccelerometers were instlled t Me Ngud Somboonchon Dm in Ching Mi. Previously the relted study on ttenution model ws minly depends on distnce of the source nd ground condition. Chintnpkdee et l. (200) [] ws studied the ttenution models which divided into severl groups depend on the ground condition. 2. MATERIALS AND METHODS 2. Detils nd equipment 2.. Detils of the erthquke On My 5th 204 t 6:0 pm mny recording instrument were detected the erthquke occurred locted on Sikow sub district, Phn district, Ching Ri, ltitude 9.65 ºE longitude ºN. The mgnitude erthquke ws 6.3 Richter nd occurred t 7 km depth from the ground. Subsequently, the erthquke dt hs nlyzed by vrious kind of dditionl informtion. inlly the ccurte nd updted dt which chnges of originl loction to new loction t ltitude 9.74 ºE longitude ºN. This new loction locted on Dong Md sub district, Me Lo district, Ching Ri. (ig. ) 2..2 Accelerometer In this study the ccelerometer ws used by men of monitoring field dt which frequency ws expressed in the form of ccelertion wves nd pek ground ccelertion (PGA). Accelerometer equipment Model version 30- SMA ws selected s shown in ig. 2. The loction of field instllment of those three points round center of the dm nd mounting position ws lso shown in ig. 3. 4

2 Y xis = 0.34 m/s2 = g = 3.2 %g Z xis = 0.30 m/s2 = 0.03 g = 3. %g 2.2 Theory ig. The epicenter on My 5th 204, Dong Md, Me Lo, Ching Ri nd detiled by from Globl CMT Ctlog [2] 2.2. Attenution model The ttenution eqution from vrious reserchers were studied nd nlyzed. The first group is Next Genertion Attenution Models (NGA), NGA is to improve nd gther informtion of the erthquke from the originl equtions. NGA composed of Abrhmson nd Silv (200)[3] nd Idriss (200)[4]. The second group is Stble Continentl Region, Stble Continentl Region is divided into groups by the type of erthquke is stble movement. It is listed of Toro et l. (997) [5], Hwng nd Huo (997) [6] nd Dhle et l. (995) [7]. ig.2 Accelerometer equipment Model version 30-SMA Considering the epicenter mesured tht the distnce hs pproximtely 0 km from Me Lo district to Me Ngud Somboonchon Dm shown in igure 4. rom field ccelerometer dt in the dm, it s hve been recorded during tht strong erthquke by showing the mximum ccelertion s following dt, X xis = 0.7 m/s2 = 0.09 g =.9 %g ig.4 The distnce between epicenter to Me Ngud Somboonchon Dm nd mximum ccelertion dt ig.3 Accelerometer nd the mounting position 49

3 The detil for clcultion this erthquke re moment mgnitude = 6.3, depth of epicenter = 7 km, distnce between epicenter to the Me Ngud Somboonchon Dm = 0 km. Group : Next Genertion Attenution Models (NGA) Abrhmson nd Silv (200) [3] Developed from the model Abrhmson nd Silv (997) used dt formt of NGA hs more complex model equtions for mximum ccelertion nd neutrl surfce s shown in Eq. () ln( PGA ) = f bse fult + AS site TOR dist unction Bse Model ( fbse ) nd is given by: ( - 2 ) (.5 - ) ( ) 4 M c M M - c ln( R + c 4 ) unction 2 ult nd Aftershock Model ( f ) nd is given by: fult + AS () (2) 2 3 NM 5 (3) AS unction 3 Site Response Model ( fsite ) nd is given by: V ( ) ln s bn V LIN unction 4 Depth-to-Top of Rupture Model ( f TOR ) nd is given by: (4) Z (- )( TOR ) (5) unction 5 Lrge Distnce Model ( fdist ) nd is given by: ( R -00)(6.5 - M) (6) M = Moment mgnitude, R = Rupture distnce (km), = lg for reverse fulting erthqukes ( for reverse nd reverse/oblique erthqukes defined by rke ngles between 30 nd 50 degrees, 0 otherwise), NM = lg for norml fulting erthqukes ( for norml erthqukes defined by rke ngles between -60 nd -20 degrees, 0 otherwise), AS = lg for ftershocks ( for ftershocks, 0 for min shocks, foreshocks, nd swrms) Tble Coefficient for mximum ccelertion (PGA) Abrhmson nd Silv (200) [3] c c n V LIN b V S Idriss (200) [4] This model estimted ground vibrtion by using the informtion in the dtbse of the erthquke of NGA depends on dt set soil types "Rock". This model is the simplest equtions s shown in Eq. (7) ( ) ( ) ( ) 2 β ( ) β 2( ) ( ) ln PSA T = T + T M - T + T M ln R γ ( T) R + ϕ( T) (7) PSA (T) = pseudo-spectrl ccelertion, (PSA) for spectrl periods of 0.0 sec, M = Moment mgnitude, R = Rupture distnce (km), = Refers to source mechnism designtor with = 0 for "strike slip/norml" events nd = for "reverse" events; Tble 2 Coefficient for mximum ccelertion (PGA) Idriss (200) [4] ( ) T 2 ( T ) β ( T ) β 2 ( T ) γ ( T ) ϕ ( T ) 0.2 Group 2 Stble Continentl Region Toro et l. (997) [5] This model cn be used for every move nd formt of hrd rock (very hrd to unwethered crystlline rock). Eq. () shown this model proposed prmeter ln( PGA) = c + c ( M 6) + c ( M 6) c ln( R) ( c4 c5) mx[ln( ),0] cr 6 00 () 50

4 jb 7 R = R + c Tble 3 Coefficient for mximum ccelertion (PGA) Toro et l. (997) [5] c c 2 c 3 c 4 C C 6 C ccelerometer dt ws nlyzed by men of dt mesurements nd their relted prmeters then the pproprite ttenution model ws concluded for suitble PGA interpret of the upper northern of Thilnd re. Me Ngud Somboonchon Dm Sikow sub-district, Phn district, Ching Ri Hwng nd Huo (997) [6] The ttenution model of Hwng nd Huo (997) [6] ws shown s following in Eq. (9) Accelerometer Moment Mgnitude=6.3 Attenution model 2 3 ln( Y ) = c+ cm+ cln[( R + H ) BR R ( M)] + c R + H (9) ( ) 0.06( M R M = e ) Tble 4 Coefficient for mximum ccelertion (PGA) Hwng nd Huo (997) [6] c c 2 c 3 c Dhle et l. (995) [7] Dhle et l. (995) [7] ttenution model ws shown with less prmeter in Eq. (0) ln( A) = c + c M + c ln R+ c R+ c S (0) 2 w h R = R + r Tble 5 Coefficient for mximum ccelertion (PGA) Dhle et l. (995) [7] c c 2 c 3 c 4 C r h Method rom the field mesurement dt of erthquke t Ching Ri with mgnitude of 6.3 Richter scle nd depth 7 km nd distnce from erthquke source bout 0 km. The ccelerometer hs detected nd monitored the vlue of PGA equl to The comprison between ccelerometer dt nd ech ttenution models ws clculted bsed on PGA vlue. The PGA determintion of ttenution models nd field Anlysis nd compred Approprite Attenution model ig.5 Methodology lowchrt NGA 3. RESULTS AND DISCUSSIONS Stble Continentl Region PGA form ttenution The nlysis of ech ttenution model bse on field ccelerometer mesuring dt ws performed. The re prmeters of ZTOR which is the depth of 7 km, R is more or less thn 0 km from the epicenter to Me Ngud Somboonchon Dm. The fult nd strike slip types were selected bse on ech ttenution model. The vlue of mximum ccelertion t surfce (PGA) of ttenution models re summrized bellows, Abrhmson nd Silv (200) [3] PGA = g Idriss (200) [4] PGA = g Toro et l. (997) [5] PGA = g Hwng nd Huo (997) [6] PGA = g Dhle et l. (995) [7] PGA = g Tble 6 The PGA from ttenution models compred to field mesurement dt Group NGA Stble Tectonic Region Attenution Models PGA(g) %Error Abrhmson Idriss Toro Hwng Dhle

5 Accelerometer Attenution Models developed ll eqution by dding vrious fctors nd consider. 5. ACKNOWLEDGEMENTS This reserch ws grnted by the Me Ngud Somboonchon Dm under Royl Irrigtion Deprtment, Ministry of Agriculture nd Coopertives, Thilnd. Sincere grtitude ws conveyed to the Construction Mngement Deprtment of Regionl Irrigtion Office Are who supervised for instrument instlltion nd dt collection while conducting field work for this study. 6. REERENCES ig.6 Clculted PGA of ttenution models compred to field mesurement dt The results of this study, we conclude tht the eqution is the northern most is Abrhmson nd Silv (200) becuse of the fctors used to clculte the rtes for the other prmeters, including the greter. The error of the eqution of productivity hs less however conclusion my not be s cler much my increse the comprison PGA into more like to collect dt from guging sttions erthquke close to the bsis or dd equtions into more will reduce error. 4. CONCLUSIONS The results of this study shown tht the most pproprited ttenution model bse of field mesurement dt for upper northern prt of Thilnd re is Abrhmson nd Silv (200) [3]. This ttenution model is suitble becuse of the fctors used to clculte nd the rtionl of prmeters ws combined in vrious viewed. The percentge error of ech model cn be reduced if we hve more field mesurement dt nd lso the erthquke source is closer distnce. When the results of this ttenution model were compred to the reding of ccelerometer, it ws found tht the Abrhmson nd Silv (200) [3] model ws very close to the reding device in the X xis of 0.09 g. The percentge error of 6.3% cn be reduced by men of energy consumption. The Abrhmson nd Silv (200) [3] model is most pproprite since this model is on NGA group which [] Chintnpkdee, C., Nguit, M. E. nd Chroenyuth, M. (200), Suitble Attenution Model for Thilnd, Chullongkorn University, Bngkok. Thilnd. [2] Meteorologicl Deprtment (204), Erthquke Report in Thilnd nd Adjcent countries in 204. [3] Abrhmson, N. A. nd Silv, W. J. (200), Summry of the Abrhmson & Silv NGA Ground Motion Reltions, Erthquke Spectr, Vol. 24, No., pp [4] Idriss, I. M. (200), An NGA Empiricl Model for Estimting the Horizontl Spectrl Vlues Generted By Shllow Crustl Erthqukes, Erthquke Spectr, Vol 24, No., pp [5] Toro, G. R., Abrhmson, N. A. nd Schneider, J.. (997), Model of Strong Ground Motions from Erthqukes in Centrl nd Estern North Americ: Best Estimtes nd Uncertinties, Seismologicl Reserch Letters, Vol. 6, No., pp [6] Hwng, H. nd Huo, J. (997), Attenution Reltions of Ground Motions for Rock nd Soil Sites in Estern United Sttes, Soil Dynmics nd Erthquke Engineering, Vol. 6, pp [7] Dhle, A., Climent, A., Tylor, W., Bungum, H., Sntos, P., Ciudd Rel, M., Lindholm, C., Struch, W. nd Segur,. (995), New Spectrl Strong Motion Attenution Models for Centrl Americ, Proceedings of the fifth Interntionl Conference on Seismic Zontion, October 7-9, Nice, rnce. Copyright Int. J. of GEOMATE. All rights reserved, including the mking of copies unless permission is obtined from the copyright proprietors. 52