Location

2006/04/14 09:27:40 35.34 89.71 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=6.0 2006/04/14 09:27:40 EVID: LAT: 35.34N, LON: 89.71E, DEPTH: 15 Mw: 6.0, mb: 0.0, Ms: 0.0 Mo= 0.123E+26 (dyne-cm) No. of Stations: 42, GAP: 92 Error (clvd/dc)*100= 5.63 Bandpass: 12 - 60 sec Nodal plane parameters strike dip rake NP1: 225 88 -9 NP2: 315 81 -178 --------------- --------------------- --------------------------- ####------------------------### #######--------------------###### ###########---------------######### ##############-----------############ #################-------############### ###################----################ ##################################### T #################----################ ###############-------############### ###############-----------############# #############---------------########### ###########-----------------######### ########--------------------####### #####------------------------#### ###--------------------------## --------------------------- --------- --------- ------ P ------ Stat Dist Az Misfit Stat Dist Az Misfit ANTO 44 293 1.43 BMR 74 24 0.98 BNI 61 306 1.09 BTDF 36 155 5.02 COLA 70 22 1.10 COLD 68 21 0.85 CSS 45 286 2.96 CUC 57 298 0.70 DPC 53 310 1.38 EIL 46 279 0.82 FFC 89 6 1.18 GAMB 62 29 0.98 GNI 35 291 2.07 IDI 51 290 1.90 ISP 46 291 1.84 KHC 55 309 0.77 KIV 36 298 3.96 KKM 38 133 0.36 KSM 38 145 0.86 KUM 31 158 0.94 KWP 49 308 1.28 LAST 51 289 2.53 MAHO 65 302 1.05 MAJO 38 73 2.46 MALT 40 289 0.85 MBAR 65 250 1.55 MDJ 31 60 1.82 MORC 53 309 1.19 MTE 72 307 0.94 OBN 41 315 1.26 SENI 60 308 0.80 SFJD 73 344 2.01 SSB 62 307 0.95 STU 58 310 0.76 SUMG 66 345 2.98 TIRR 46 300 1.97 TIXI 41 17 15.00 TNA 63 27 0.87 TRI 56 305 2.04 TUE 59 307 1.25 WLF 60 311 0.92 WRAB 69 135 0.55 Misfit > 1 heavily downweighted

06/04/14 09:27:40.75 WESTERN XIZANG Epicenter: 35.344 89.706 MW 5.6 USGS MOMENT TENSOR SOLUTION Depth 5 No. of sta: 22 Moment Tensor; Scale 10**17 Nm Mrr=-3.11 Mtt= 2.09 Mff= 1.02 Mrt= 0.15 Mrf= 0.04 Mtf= 1.90 Principal axes: T Val= 3.53 Plg= 1 Azm=323 N -0.42 1 53 P -3.11 88 186 Best Double Couple:Mo=3.3*10**17 NP1:Strike= 52 Dip=44 Slip= -92 NP2: 234 46 -88 ####### ################# T ################### # ##################### ##############--------------# ############-----------------## #########--------------------## ########---------------------#### #######-------- -----------#### ######--------- P ----------##### #####---------- ---------###### ####---------------------######## ##--------------------######### ##------------------########### #---------------############# #--------################ ##################### ################# #######

pril 14, 2006, WESTERN XIZANG, MW=5.6 Goran Ekstrom CENTROID, MOMENT TENSOR SOLUTION HARVARD EVENT-FILE NAME C041406A DATA USED: GSN L.P. BODY WAVES: 49S, 90C, T= 40 SURFACE WAVES: 64S,132C, T= 50 CENTROID LOCATION: ORIGIN TIME 09:27:47.5 0.1 LAT 35.45N 0.01;LON 89.71E 0.01 DEP 17.3 0.5;HALF-DURATION 1.6 MOMENT TENSOR; SCALE 10**24 D-CM MRR=-2.27 0.07; MTT=-0.98 0.06 MPP= 3.25 0.06; MRT= 0.45 0.16 MRP= 0.67 0.16; MTP= 2.28 0.05 PRINCIPAL AXES: 1.(T) VAL= 4.34;PLG= 7;AZM=294 2.(N) -1.93; 18; 26 3.(P) -2.41; 70; 184 BEST DOUBLE COUPLE:M0=3.4*10**24 NP1:STRIKE= 4;DIP=41;SLIP=-118 NP2:STRIKE=220;DIP=54;SLIP= -67 ########--- ##############----- ################--##### ##############-------###### ###########----------###### T #########------------####### #######---------------###### ##########----------------####### ########------------------####### ########------------------####### #######-------- --------####### #####--------- P -------####### #####--------- -------####### ####------------------####### ###-----------------####### #----------------###### -------------###### ------#####

Deviatoric Moment Tensor Solution

The following broadband stations were used for the source inversion: ANTO BMR BNI BTDF COLA COLD CSS CUC DPC EIL FFC GAMB GNI IDI ISP KHC KIV KKM KSM KUM KWP LAST MAHO MAJO MALT MBAR MDJ MORC MTE OBN SENIN SFJD SSB STU SUMG TIRR TIXI TNA TRI TUE WLF WRAB

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.)]

All observed and Greens function waveforms are corrected to instrument response to ground velocity in meters/sec for the passband of 0.01 - 5 Hz. Next tre traces were bandpass filtered by the application of the following high- and low-pass stages:

hp c 0.0167 2
lp c 0.0833 2
br c 0.12 0.25 n 4 p 2
br c 0.12 0.25 n 4 p 2

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  225.   88.   -9.   6.03     0.088 0.296E-06     0.136     0.332 0.199E-06   5.6

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