Location

2006/05/10 02:42:56 52.71 -169.24 56

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.

Note that the SLU solution agrees better with historical mechanisms there than either the Harvard or USGS solutions ( Other moment tensors )

SLU	USGS	HARVARD CMT
Mw=6.2 2006/05/10 02:42:56 EVID: LAT: 52.71N, LON: 169.24W, DEPTH: 25 Mw: 6.2, mb: 0.0, Ms: 0.0 Mo= 0.260E+26 (dyne-cm) No. of Stations: 67, GAP: 59 Error (clvd/dc)*100= 48.48 Bandpass: 12 - 60 sec Nodal plane parameters strike dip rake NP1: 80 73 84 NP2: 279 18 108 --------------- --------------------- ----#################------ ---########################---- --############################--- -############# ################-- -############## T #################-- -############### ##################-- ######################################- #####################################-# ##################################----- #############################---------- -######################---------------- --------------------------------------- ------------------------------------- ----------------------------------- --------------------------------- --------------- ------------- ------------- P ----------- ---------- -------- --------------- Stat Dist Az Misfit Stat Dist Az Misfit 116A 45 92 0.53 ACSO 57 65 0.27 AFI 66 182 0.68 AQU 85 358 0.23 ARU 64 332 0.16 BBSR 72 58 0.31 BNLO 36 96 0.89 CBKS 48 77 0.42 CEL 89 355 0.15 CHTO 76 282 0.21 CWC 39 93 0.92 D04A 29 81 0.76 DAV 69 254 0.52 DPC 77 356 0.16 EIDS 85 215 0.86 EKS2 70 315 0.21 ESK 71 8 0.22 FITZ 90 239 0.59 GRFO 77 359 0.14 GUMO 53 240 0.31 GVD 92 349 0.27 HNR 67 213 0.66 ISCO 44 80 0.48 KIP 32 160 0.66 KIV 79 337 0.20 L02A 32 90 0.82 LGU 39 97 0.82 M05C 34 89 0.70 MALT 86 338 0.22 MAUI 33 157 0.62 MNTX 49 88 0.43 N02C 33 92 0.89 O05C 35 91 0.68 OBIP 83 69 1.00 OUZ 88 193 0.72 PAB 87 11 0.18 PMG 72 225 0.46 POHA 34 156 1.08 PPCW 55 67 0.99 RAR 74 170 0.99 RUE 75 358 0.18 S05C 37 94 0.85 SANT 90 348 0.31 SDV 88 77 0.31 SLM 54 71 0.32 SNZO 94 192 0.85 SSB 82 4 0.26 STKA 94 220 0.57 STU 78 1 0.20 TKM2 69 314 0.13 TRO 41 95 0.73 TUC 46 92 0.48 TUE 81 0 0.20 TUQ 40 93 0.79 ULN 50 300 0.27 URZ 91 190 0.95 USIN 56 70 0.24 VSU 68 351 0.16 VTS 84 350 0.17 WRAB 87 231 0.52 X15A 43 91 0.58 Y12C 42 93 0.63 Y22C 47 87 0.44 YNG 94 214 0.64 YSS 31 278 0.27 YULB 59 268 0.37 ZKR 91 347 0.27 Misfit > 1 heavily downweighted	Mw=6.2 FOX ISLANDS, ALEUTIAN ISLANDS 2006/05/10 02:42:56.30 EVID: MNAG LAT: 52.71N, LON: 169.24W, DEPTH: 30 Mw: 6.2, mb: 6.3, Ms: 6.3 Mo= 0.203E+26 (dyne-cm) No. of Stations: 13, GAP: 175 Error (clvd/dc)*100= 14.43 Nodal plane parameters strike dip rake NP1: 59 53 88 NP2: 243 37 93 ---------- -------------------- -------------------------- -----------------#####-------- ------------##################-- ---------######################### --------###########################- -------#############################-- -----##############################--- -----##############################----- ----##############################------ ---##############################------- ---############################--------- -###########################---------- -#########################------------ ######################-------------- #################----------------- -------------------------------- ------------------------------ -------------------------- -------------------- ---------- Stat Dist Az Misfit Stat Dist Az Misfit ANMO 47 86 0.39 FCC 40 50 0.41 FFC 38 59 0.45 HKT 56 82 0.53 HLID 36 81 0.95 ISCO 44 80 0.46 KBS 48 359 0.38 MAJO 39 267 0.93 RSSD 42 74 0.27 TUC 46 92 0.56 WDC 33 92 0.88 YAK 33 310 0.64 YSS 31 278 0.34 Median of misfit: 0.46 Average misfit: 0.55	May 10, 2006, FOX ISLANDS, ALEUTIAN ISLANDS, MW=6.4 Natasha Maternovskaya CENTROID, MOMENT TENSOR SOLUTION HARVARD EVENT-FILE NAME C051006A DATA USED: GSN L.P. BODY WAVES: 87S,230C, T= 40 MANTLE WAVES: 79S,170C, T=125 CENTROID LOCATION: ORIGIN TIME 02:42:56.5 0.1 LAT 52.24N 0.01;LON 169.25W 0.01 DEP 31.7 0.5;HALF-DURATION 3.9 MOMENT TENSOR; SCALE 10**25 D-CM MRR= 3.66 0.03; MTT=-3.20 0.03 MPP=-0.46 0.03; MRT= 2.99 0.08 MRP= 1.51 0.07; MTP=-1.49 0.02 PRINCIPAL AXES: 1.(T) VAL= 4.94;PLG=69;AZM=331 2.(N) 0.19; 2; 65 3.(P) -5.13; 21; 156 BEST DOUBLE COUPLE:M0=5.0*10**25 NP1:STRIKE=249;DIP=24;SLIP= 94 NP2:STRIKE= 64;DIP=66;SLIP= 88 ----------- ------------------- -------############---- ------###################-- ----########################- ----######## ###############- --########## T ##############-- --########### ############----- --#########################------ -#######################--------- -#####################----------- #################-------------- #############------------------ ----------------------------- ----------------- ------- --------------- P ----- ------------- --- -----------

Deviatoric Moment Tensor Solution

The following broadband stations were used for the source inversion: 116A ACSO AFI AQU ARU BBSR BNLO CBKS CEL CHTO CWC D04A DAV DPC EIDS EKS2 ESK FITZ GRFO GUMO GVD HNR ISCO KIP KIV L02A LGU M05C MALT MAUI MNTX N02C O05C OBIP OUZ PAB PMG POHA PPCWF RAR RUE S05C SANT SDV SLM SNZO SSB STKA STU TKM2 TRO TUC TUE TUQ ULN URZ USIN VSU VTS WRAB X15A Y12C Y22C YNG YSS YULB ZKR

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

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   25.0   80.   73.   84.   6.24     0.006 0.132E-04     0.506     0.085 0.687E-06  48.5

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