Data focal mechanisms atau CMT-solution di bawah menunjukan bahwa gempa ini adalah strike-slip faulting. Lokasinya ada di lempeng Samudra Hindia. Di Lempeng samudra ini struktur yang dominan adalah "transform ridges"yang berarah NNE-SSW, yang paling besar dinamai Investigator Fracture Zone (IFZ)". Gempa M 7.3 ini posisinya diantara IFZ dan palung Sumatra.
Nah melihat posisi tektoniknya ini, kelihatannya gempa ini adalah strike-slip fault - SINISTRAL (lihat CMT solution di bawah - kemungkinannya dekstral dengan strike ENE-WNW atau sinistral dengan strike NNE-SSW). Sebetulnya system transform fault NNE-SSW ini sudah tidak aktif lagi , tapi pergerakan tektonik sekarang membuat BLOK BESAR LEMPENG SAMUDRA HINDIA BER_ROTASI SEARAH JARUM JAM sehingga menyebabkan system patahan strike-slip ini DIREAKTIFASI LAGI (mekanisme DOMNO PRINCIPLE). Gempa seperti ini sudah banyak terjadi. Waktu setelah gempa Bengkulu tahun 2000 juga terjadi gempa strike-slip sinistral di Lautan Hindia dengan magnitude Mw7.9. Yang saya heran, Gempa besar M 7.3 ini kok LUPUT TIDAK DI BROADCAST BMKG ya? Salam, Danny Catatan: yang mau lihat langsung laporan USGS ikut saja link ini: http://earthquake.usgs.gov/earthquakes/recenteqsww/Quakes/usc0007ir5.php ---Lampiran CMT-USGS------------- January 10, 2012, OFF W COAST OF NORTHERN SUMATRA, MW=7.2 Meredith Nettles CENTROID-MOMENT-TENSOR SOLUTION GCMT EVENT: C201201101837A DATA: II LD IU CU MN G IC GE DK L.P.BODY WAVES:146S, 349C, T= 50 MANTLE WAVES: 148S, 343C, T=150 SURFACE WAVES: 136S, 330C, T= 50 TIMESTAMP: Q-20120110175354 CENTROID LOCATION: ORIGIN TIME: 18:37:13.2 0.1 LAT: 2.51N 0.00;LON: 92.99E 0.00 DEP: 14.2 0.4;TRIANG HDUR: 9.6 MOMENT TENSOR: SCALE 10**26 D-CM RR=-0.432 0.023; TT=-2.870 0.020 PP= 3.300 0.023; RT=-1.850 0.119 RP=-1.400 0.117; TP=-6.010 0.020 PRINCIPAL AXES: 1.(T) VAL= 6.978;PLG= 2;AZM= 59 2.(N) 0.335; 71; 154 3.(P) -7.315; 19; 328 BEST DBLE.COUPLE:M0= 7.15*10**26 NP1: STRIKE=105;DIP=76;SLIP=-168 NP2: STRIKE= 12;DIP=78;SLIP= -15 ---------## - ---------###### --- P ---------######## ----- ---------######### ------------------######### T -------------------######### -------------------############ ###----------------############## ######-------------############## ##########---------############## ###############---############### #################--------#####- ################--------------- ###############-------------- #############-------------- ##########------------- #######------------ ##--------- From: yudieiskan...@gmail.com [mailto:yudieiskan...@gmail.com] Sent: Wednesday, January 11, 2012 7:47 AM To: iagi-net@iagi.or.id Subject: Re: [iagi-net-l] Fwd: AEIC EarthQuake Information -- Info Gempa Mag:5.0 SR, 11-Jan-12 04:00:53 WIB, Lok:2.39 LU,93.18 BT (325 km BaratDaya KAB-SIMEULUE), Kedlmn:59 Km ::BMKG Artinya apa kang Danny.. Mohon pencerahannya dong Nuhun Yudie Sent from my own powered by ABC _____ From: "Danny Hilman Natawidjaja" <danny.hil...@gmail.com> Date: Wed, 11 Jan 2012 07:22:12 +0700 To: <iagi-net@iagi.or.id>; 'Forum HAGI'<fo...@hagi.or.id> ReplyTo: <iagi-net@iagi.or.id> Subject: RE: [iagi-net-l] Fwd: AEIC EarthQuake Information -- Info Gempa Mag:5.0 SR, 11-Jan-12 04:00:53 WIB, Lok:2.39 LU,93.18 BT (325 km BaratDaya KAB-SIMEULUE), Kedlmn:59 Km ::BMKG Benar. Lokasinya di oceanic plate. Yang jelas ini bukan thrusting di zona subduksi (megathrust) From: Rovicky Dwi Putrohari [mailto:rovi...@gmail.com] Sent: Wednesday, January 11, 2012 7:00 AM To: IAGI; Forum HAGI Subject: [iagi-net-l] Fwd: AEIC EarthQuake Information -- Info Gempa Mag:5.0 SR, 11-Jan-12 04:00:53 WIB, Lok:2.39 LU,93.18 BT (325 km BaratDaya KAB-SIMEULUE), Kedlmn:59 Km ::BMKG Kalau melihat lokasinya sepertinya bukan thrust ya? Rdp ---------- Forwarded message ---------- From: ASEAN Earthquake Information Centre Date: Wednesday, January 11, 2012 Subject: AEIC EarthQuake Information -- Info Gempa Mag:5.0 SR, 11-Jan-12 04:00:53 WIB, Lok:2.39 LU,93.18 BT (325 km BaratDaya KAB-SIMEULUE), Kedlmn:59 Km ::BMKG To: rovi...@gmail.com Event: Public ID bmg2012asbd Preferred Origin ID Origin#20120110210445.065487.34441 Preferred Magnitude ID Origin#20120110210445.065487.34441#netMag.M Description region name: Off West Coast of Northern Sumatra Creation time 2012-01-10 21:03:28 Origin: Public ID Origin#20120110210445.065487.34441 Date 2012-01-10 Time 21:00:53.2 +/- 0.7 s Latitude 2.39 deg +/- 6 km Longitude 93.18 deg +/- 6 km Depth 59 km +/- 51 km Agency BMG Mode manual Status confirmed Creation time 2012-01-10 21:04:45 Residual RMS 0.6 s Azimuthal gap 166 deg 5 Network magnitudes: MLv 5.15 +/- 0.16 4 BMG mb 4.72 +/- 0.25 6 BMG mB 4.44 1 BMG Mw(mB) 3.59 1 BMG M 5.01 6 preferred BMG 16 Phase arrivals: sta net dist azi phase time res wt sta SNSI IA 3.1 90 P 21:01:40.4 0.2 M 1.0 SNSI MLSI IA 3.7 60 P 21:01:47.6 -0.5 M 1.0 MLSI TPTI IA 4.1 78 P 21:01:53.1 0.0 M 1.0 TPTI GSI IA 4.5 104 P 21:01:58.8 -0.4 M 1.0 GSI LHMI IA 4.7 53 P 21:02:01.9 0.3 M 1.0 LHMI KCSI IA 4.7 76 P 21:02:03.2 1.4 M 1.0 KCSI PSI PS 5.7 87 P 21:02:16.2 0.3 M 1.0 PSI PSI IA 5.7 87 P 21:02:16.1 0.2 M 1.0 PSI PKDT TM 7.5 43 P 21:02:38.7 -1.2 M 1.0 PKDT KUM MY 8.0 69 P 21:02:45.9 -0.7 M 1.0 KUM IPM MY 8.1 75 P 21:02:47.8 -0.4 M 1.0 IPM MASI IA 10.6 121 P 21:03:22.2 -0.1 M 1.0 MASI PHET TM 12.2 31 P 21:03:45.2 0.3 M 1.0 PHET HALK GE 13.0 287 P 21:03:55.1 -0.0 M 1.0 HALK SRDT TM 13.2 26 P 21:03:59.1 0.6 M 1.0 SRDT MALK GE 13.9 296 P 21:04:08.8 1.1 MX 0.0 MALK 13 Station magnitudes: sta net dist azi type value res amp per SNSI IA 3.1 90 MLv 5.34 0.19 N/A N/A MLSI IA 3.7 60 MLv 5.21 0.06 N/A N/A TPTI IA 4.1 78 MLv 4.91 -0.25 N/A N/A GSI IA 4.5 104 MLv 5.12 -0.03 2.49317 PSI PS 5.7 87 mb 4.56 -0.16 55.104 0.96 PSI IA 5.7 87 mb 4.31 -0.41 30.084 0.94 PKDT TM 7.5 43 mb 4.60 -0.12 N/A N/A KUM MY 8.0 69 mb 4.80 0.07 N/A N/A IPM MY 8.1 75 mb 4.88 0.16 N/A N/A MASI IA 10.6 121 mb 5.41 0.69 N/A N/A PHET TM 12.2 31 mB 4.44 0.00 N/A N/A PHET TM 12.2 31 mb 4.39 -0.33 N/A N/A HALK GE 13.0 287 mb 5.09 0.37 N/A N/A -- "Sejarah itu tidak pernah usang untuk terus dipelajari"
