Location

2006/04/01 10:02:19 22.90 121.25 10

Moment Tensor Comparison

The following compares this source inversion to the USGS Rapid Moment Tensor Solution and to the Harvard CMT solutions, if they are available.

Mw=6.1 2006/04/01 10:02:19 EVID: LAT: 22.90N, LON: 121.25E, DEPTH: 30 Mw: 6.1, mb: 0.0, Ms: 0.0 Mo= 0.155E+26 (dyne-cm) No. of Stations: 70, GAP: 55 Error (clvd/dc)*100= 25.03 Bandpass: 12 - 60 sec Nodal plane parameters strike dip rake NP1: 76 81 160 NP2: 170 70 10 -######### ------############## --------################## ----------#################### ----------###################### -----------####################### ------------######################## -------------######################### -------------######################### ---------------#####################---- ---------------################--------- ---------------###########-------------- ---------------###---------------------- -------########----------------------- ###############----------------------- ###############--------------------- ###############------------------- ##############------------------ ##############---------------- #############------------- ############-------- ########-- Stat Dist Az Misfit Stat Dist Az Misfit ADK 55 41 0.61 AFI 75 112 0.90 AKUT 61 39 0.63 AQU 87 315 0.60 ARU 56 323 0.43 ATKA 56 41 0.57 BBOO 57 165 0.88 BESE 77 31 1.08 BILL 52 19 0.46 BMR 72 30 0.56 BPAW 68 28 0.93 BRVK 48 321 0.91 CRAG 79 33 1.05 CUC 86 312 0.77 D03A 89 38 0.93 D04A 89 37 0.98 DSB 91 331 0.82 FORT 53 172 26.93 GNI 65 305 0.61 GRFO 84 322 0.55 GVD 82 304 0.68 HEBO 90 39 0.93 HLG 84 327 0.64 I05A 92 39 0.99 IBBN 85 325 0.67 IDI 82 304 0.65 ISP 76 305 0.51 K06A 93 40 0.92 KBS 71 348 0.62 KEV 70 338 0.63 KIP 73 73 0.99 KMBL 53 179 3.83 KSDI 74 299 0.86 KURK 43 320 0.32 KWP 78 318 0.60 M04C 93 41 0.98 MALT 70 304 0.56 MAUI 75 73 0.96 MBAR 90 269 0.95 MBWA 43 182 1.14 MCK 69 28 1.03 MUN 54 185 0.99 NIKO 60 41 0.61 NWAO 55 184 1.51 PET 41 33 0.77 PMG 40 138 0.77 RAO 78 128 0.82 RAR 88 113 0.98 RER 77 240 0.75 RGN 81 325 0.58 SDPT 64 38 0.56 SMY 49 39 0.97 SNZO 80 142 0.68 STKA 57 159 0.85 SUMG 83 353 0.75 TIP 86 311 0.67 TIR 83 311 0.68 TIRR 76 312 0.48 TRF 69 28 0.57 TUE 87 320 0.66 UNV 61 39 0.63 VLC 88 317 0.68 VOS 48 321 0.53 VSL 91 314 0.68 VSU 73 326 0.56 VTS 80 312 0.52 WRAB 44 162 0.99 YAK 39 6 0.57 YBH 92 42 0.95 YNG 62 154 0.71 Misfit > 1 heavily downweighted

Mw=6.2 TAIWAN REGION 2006/04/01 10:02:20.46 EVID: KZAW LAT: 22.91N, LON: 121.20E, DEPTH: 70 Mw: 6.2, mb: 6.1, Ms: 6.1 Mo= 0.223E+26 (dyne-cm) No. of Stations: 18, GAP: 277 Error (clvd/dc)*100= 83.80 Nodal plane parameters strike dip rake NP1: 52 59 153 NP2: 157 67 34 ########## --################## -----##################### ------######################## -------######################### ---------########################- ----------#######################--- -----------######################----- ------------#####################----- -------------####################------- --------------#################--------- --------------################---------- ---------------#############------------ ---------------##########------------- ----------------#######--------------- ----------------###----------------- ---------------#------------------ ---------########--------------- #################------------- #################--------- ################---- ########## Stat Dist Az Misfit Stat Dist Az Misfit ARU 56 323 1.03 BILL 52 19 0.62 COLA 69 27 0.45 FCC 93 17 0.42 INK 74 21 0.46 KBS 71 348 0.77 KEV 70 338 0.77 KONO 80 331 0.99 MA2 42 21 0.51 MORC 81 320 1.15 NEW 92 34 0.41 OBN 68 322 0.98 PET 41 33 0.64 SIT 78 32 0.42 WDC 93 43 0.51 WLF 87 323 0.93 YAK 39 6 0.65 YSS 29 30 0.76 Median of misfit: 0.64 Average misfit: 0.69

April 1, 2006, TAIWAN REGION, MW=6.2 Natasha Maternovskaya CENTROID, MOMENT TENSOR SOLUTION HARVARD EVENT-FILE NAME C040106B DATA USED: GSN L.P. BODY WAVES: 83S,201C, T= 40 MANTLE WAVES: 78S,136C, T=125 CENTROID LOCATION: ORIGIN TIME 10:02:22.0 0.1 LAT 22.80N 0.01;LON 121.00E 0.02 DEP 26.5 1.2;HALF-DURATION 2.8 MOMENT TENSOR; SCALE 10**25 D-CM MRR= 0.28 0.02; MTT=-0.92 0.02 MPP= 0.64 0.02; MRT= 1.04 0.06 MRP=-1.22 0.07; MTP=-1.45 0.02 PRINCIPAL AXES: 1.(T) VAL= 2.59;PLG=34;AZM= 57 2.(N) -0.76; 53; 260 3.(P) -1.84; 11; 154 BEST DOUBLE COUPLE:M0=2.2*10**25 NP1:STRIKE=201;DIP=58;SLIP= 18 NP2:STRIKE=101;DIP=75;SLIP= 146 ----------- ------------####### ------------########### ------------############### ------------########## #### -----------############ T ##### ----------############# ##### #----------###################### ####------####################### ########-######################## #########-----################### ########----------------------- ########----------------------- #######---------------------- ######--------------------- ####------------ ---- ###----------- P -- ----------

IES BATS moment-tensor solution : -40.5352020 151.8170013 41.2512016 151.8170013 14.4167013 66.2492981 x 10+E16 Nt-m 41.2512016 66.2492981 2.7104602 Centroid depth : 22 km Mw : 6.10 Average MISFIT : 0.496 ( The fit is good ) Best double couple solutions : nodal plane(1) strike/dip/slip: 92/ 70/ 165 nodal plane(2) strike/dip/slip: 187/ 76/ 20 --------#### -----------######### P ----------############# -- ---------########## ### ---------------########## T #### ---------------########### ##### ----------------#################### ---------------##################### ###------------####################- ##########-----##############------- ##############-------------------- ############-------------------- ############------------------ ##########---------------- #######------------- ####--------

Deviatoric Moment Tensor Solution

The following broadband stations were used for the source inversion: ADK AFI AKUT AQU ARU ATKA BBOO BESE BILL BMR BPAW BRVK CRAG CUC D03A D04A DSB FORT GNI GRFO GVD HEBO HLG I05A IBBN IDI ISP K06A KBS KEV KIP KMBL KSDI KURK KWP M04C MALT MAUI MBAR MBWA MCK MUN NIKO NWAO PET PMG RAO RAR RER RGN SDPT SMY SNZO STKA SUMG TIP TIR TIRR TRF TUE UNV VLC VOS VSL VSU VTS WRAB YAK YBH YNG

Location of the earthquake (yellow star) and great circle path from the epicenter to each station (red) [created using GMT (Wessel, P., and W. H. F. Smith, New version of Generic Mapping Tools released, EOS Trans. AGU, 76 329, 1995.)]

The traces were next integrated to ground displacment in meters. Finally waveforms were cut from 30 seconds before to 140 seconds after the P arrival so that the direct P wave, pP and perhaps the sP are included.

The source inversion is a multipass operation since a lower frequency filter band is used for larger earthquakes and since a search is made over depth. Up to three passed of the outer loop are made, after which the moment magnitude is determined and filter settings readjusted. The inner loop over depth samples all depths from 0 to 800 km with 5 km increments in depth to 50 km, followed by 10 km depth sampling for the remaining range.

The following filter ranges are used according to the moment magnitude Mw:

   FILTER_BAND   FH(s)  FL(s)
       1           60     12      Mw < 6.4
       2          100     20      6.4 < Mw <= 6.9
       3          120     40      Mw > 6.9

For this data set the favored solution is

WVFMTD96   30.0   76.   81.  160.   6.09     0.017 0.178E-05     0.083     0.137 0.631E-06  25.0

The following figures show the sensitivity of the goodness of fit parameter so source depth, the waveform comparison as a function of epicentral distance in degrees and the source to station azimuth

Depth Sensitivity

Goodness of fit as a function of source depth. The measure is 1 - SUM (o -p)2 / SUM o2. A value of 1.0 is the best fit. The best double couple mechanism for the solution depth is plotted above goodness of fit value to indicate how the mefhanism may change with depth.

Fit with Distance

Fit with Azimuth

Comparison of the observed traces (red) and solution predicted traces (blue) as a function of source to station azimuth in degrees (D). The purpose of this display is to highlight the azimuthal dependence on the first motion. The traces are annotated with the station name at the top.

Inversion Details