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 10:02:20 EVID: LAT: 22.90N, LON: 121.25E, DEPTH: 15 Mw: 6.1, mb: 0.0, Ms: 0.0 Mo= 0.136E+26 (dyne-cm) No. of Stations: 17, GAP: 277 Error (clvd/dc)*100= 53.69 Nodal plane parameters strike dip rake NP1: 259 70 -130 NP2: 147 44 -29 ########## #################### -######################### ---########################### ---############################# ----############################## -----############################### ------################################ ------###########--------------------# -------#####---------------------------- -------#-------------------------------- ----####-------------------------------- -########------------------------------- #########----------------------------- ##########---------------------------- ##########-------------------------- ###########----------------------- ############-------------------- #############----------------- ###############----------- #################### ########## Stat Dist Az Misfit Stat Dist Az Misfit ARU 56 323 0.56 BILL 52 19 0.51 COLA 69 27 0.61 FFC 94 23 0.61 KBS 71 348 0.45 KEV 70 338 0.41 KONO 80 331 0.46 MA2 42 21 0.59 MORC 81 320 0.49 NEW 92 34 0.70 OBN 68 322 0.57 PET 41 33 0.80 SIT 78 32 0.69 WDC 93 43 0.64 WLF 87 323 0.47 YAK 39 6 0.38 YSS 29 30 0.81 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: ARU BILL COLA FFC KBS KEV KONO MA2 MORC NEW OBN PET SIT WDC WLF YAK YSS

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   15.0  259.   70. -130.   6.06     0.343 0.434E-06     0.343     0.581 0.434E-06  53.7

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