Location

2006/05/16 10:39:23 -31.56 -179.30 148

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.

SLU	USGS	HARVARD CMT
Mw=7.5 2006/05/16 10:39:23 EVID: LAT: 31.56S, LON: 179.30W, DEPTH: 160 Mw: 7.5, mb: 0.0, Ms: 0.0 Mo= 0.175E+28 (dyne-cm) No. of Stations: 49, GAP: 85 Error (clvd/dc)*100= 37.09 Bandpass: 40 - 100 sec Nodal plane parameters strike dip rake NP1: 13 76 103 NP2: 150 19 48 ############--- ###############------ -##################-------- --###################---------- --####################----------- --####################------------- --#####################-------------- ---######## ##########--------------- ---######## T ##########--------------- ---######## #########--------- ---- ---####################--------- P ---- ---####################--------- ---- ---###################----------------- ----##################----------------- ----################----------------- ----##############----------------- ----#############---------------- -----##########---------------- -----#######--------------- ------##------------- ----########### Stat Dist Az Misfit Stat Dist Az Misfit ATKA 83 3 0.40 BBOO 37 255 0.40 C05A 94 34 0.55 CASY 53 208 0.71 COCO 78 262 0.09 CTAO 32 281 0.08 D05A 93 35 0.58 DAV 65 296 0.85 EFI 82 147 0.21 FITZ 51 271 0.38 FORT 44 256 51.92 G05A 92 36 0.54 INCN 85 319 0.20 KDAK 91 13 0.59 KIP 56 23 0.47 KMBL 49 253 0.97 KOM 79 278 0.07 KSM 74 281 0.10 LDM 69 289 0.11 M09A 92 41 0.48 M11A 93 42 0.51 MAUI 56 26 0.54 MBWA 55 265 0.09 MIDW 59 1 0.58 NACB 79 307 0.14 NEE 89 48 0.42 NIKO 84 6 0.46 NWAO 52 250 0.13 P09A 91 43 0.50 PKD 86 44 0.45 PLCA 82 133 0.16 PMG 38 297 0.07 PMSA 71 155 0.52 POHA 55 27 0.52 Q03C 87 41 0.46 Q04C 88 41 0.47 Q09A 90 43 0.50 QSPA 58 180 0.86 S08C 89 44 0.45 SBC 86 45 0.39 SBM 73 283 0.08 SMY 84 355 0.42 STKA 33 258 0.03 TPH 90 44 0.44 UNV 85 7 0.47 VCS 87 46 0.43 VNDA 46 185 1.17 WRAB 43 274 0.06 YHNB 79 307 0.59 Misfit > 1 heavily downweighted	Mw=7.3 KERMADEC ISLANDS REGION 2006/05/16 10:39:23.55 EVID: MUAH LAT: 31.56S, LON: 179.30W, DEPTH: 160 Mw: 7.3, mb: 7.4, Ms: 7.4 Mo= 0.109E+28 (dyne-cm) No. of Stations: 15, GAP: 199 Error (clvd/dc)*100= 71.40 Nodal plane parameters strike dip rake NP1: 265 59 124 NP2: 32 45 47 ---------- -------------------- ------------------------## ---------------------------### -----------------------------### ------------------------------#### -------------------------------##### ------------##################--###### -------#########################---### -----############################------# --##############################-------- -###############################-------- ###############################--------- #############################--------- ############################---------- ##########################---------- #######################----------- ####################------------ ################-------------- ###########--------------- -------------------- ---------- Stat Dist Az Misfit Stat Dist Az Misfit CHTO 92 290 0.33 CMB 88 42 0.26 COCO 78 262 0.26 COR 91 36 0.34 CTAO 32 281 0.88 DAV 65 296 0.35 HNR 29 314 0.85 INCN 85 319 0.55 MAJO 78 326 0.55 MOD 91 39 0.39 NWAO 52 250 0.14 TATO 79 307 0.33 TUC 90 51 0.22 WDC 88 39 0.35 YSS 85 334 0.63 Median of misfit: 0.35 Average misfit: 0.43	Natasha Maternovskaya CENTROID, MOMENT TENSOR SOLUTION HARVARD EVENT-FILE NAME C051606A DATA USED: GSN L.P. BODY WAVES: 80S,229C, T= 50 MANTLE WAVES: 79S,221C, T=150 CENTROID LOCATION: ORIGIN TIME 10:39:36.8 0.1 LAT 31.31S 0.01;LON 178.92W 0.01 DEP 154.6 1.0;HALF-DURATION 12.6 MOMENT TENSOR; SCALE 10**27 D-CM MRR= 1.01 0.01; MTT=-0.49 0.01 MPP=-0.53 0.01; MRT=-0.24 0.01 MRP= 1.38 0.01; MTP= 0.38 0.01 PRINCIPAL AXES: 1.(T) VAL= 1.82;PLG=60;AZM=269 2.(N) -0.30; 11; 160 3.(P) -1.53; 28; 64 BEST DOUBLE COUPLE:M0=1.7*10**27 NP1:STRIKE=126;DIP=20;SLIP= 55 NP2:STRIKE=343;DIP=74;SLIP= 102 #---------- ######------------- ##########------------- #############-------------- -##############-------------- -################-------- --- -################-------- P --- --#################------- ---- --####### ########------------- --####### T ########------------- ---###### #########------------ --##################----------- ---#################----------- ----################--------- -----##############-------# -----############-----# --------########### ----------#

Deviatoric Moment Tensor Solution

The following broadband stations were used for the source inversion: ATKA BBOO C05A CASY COCO CTAO D05A DAV EFI FITZ FORT G05A INCN KDAK KIP KMBL KOM KSM LDM M09A M11A MAUI MBWA MIDW NACB NEE NIKO NWAO P09A PKD PLCA PMG PMSA POHA Q03C Q04C Q09A QSPA S08C SBC SBM SMY STKA TPH UNV VCS VNDA WRAB YHNB

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 0.0083 2
lp c 0.0250 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  160.0   13.   76.  103.   7.46     0.654 0.141E-04     0.672     0.809 0.121E-04  37.1

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