Location

2006/04/12 16:52:03 37.67 21.13 20

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=5.6 2006/04/12 16:52:03 EVID: LAT: 37.67N, LON: 21.13E, DEPTH: 20 Mw: 5.6, mb: 0.0, Ms: 0.0 Mo= 0.313E+25 (dyne-cm) No. of Stations: 18, GAP: 96 Error (clvd/dc)*100= 38.81 Bandpass: 12 - 60 sec Nodal plane parameters strike dip rake NP1: 167 87 138 NP2: 259 48 4 ###------------ ######--------------- ##########----------------- ############------------------- #############-------------------- #############--##############------ #########-------##################--- #######-----------###################-- #####-------------##################### ###---------------##################### ##-----------------#################### #------------------#################### --------------------########### ##### --------------------########### T ##### --------------------########## #### ------ ----------################ ----- P -----------############## ---- -----------############# -----------------########## --------------####### ------------### Stat Dist Az Misfit Stat Dist Az Misfit ALLY 73 309 0.96 ARU 31 40 0.50 BILL 71 13 0.76 COLD 75 356 0.84 DBIC 38 223 1.11 EKS2 40 65 0.33 KBK 40 65 0.25 KSU1 84 316 0.97 KURK 42 52 0.40 LBTB 62 175 0.86 LSA 57 75 0.57 LSZ 53 171 0.71 OXF 83 308 1.03 SUMG 45 338 1.28 ULHL 41 65 0.31 ULN 60 50 0.38 WRPS 72 308 1.00 YAK 65 29 0.41 Misfit > 1 heavily downweighted

06/04/12 16:52: 3.15 SOUTHERN GREECE Epicenter: 37.666 21.129 MW 5.6 USGS MOMENT TENSOR SOLUTION Depth 22 No. of sta: 19 Moment Tensor; Scale 10**17 Nm Mrr= 1.70 Mtt= 0.74 Mff=-2.44 Mrt= 0.80 Mrf=-1.38 Mtf= 0.16 Principal axes: T Val= 2.43 Plg=62 Azm= 31 N 0.47 20 167 P -2.90 18 263 Best Double Couple:Mo=2.7*10**17 NP1:Strike= 22 Dip=33 Slip= 130 NP2: 157 66 67 ####### --##############- ---################-- -----#################--- -------##################---- ---------#################----- ---------######## #######---- ----------######## T #######----- -----------####### #######----- - --------################----- - P --------###############------ - ---------##############------ -------------############------ --------------##########------- ---------------######-------- --------------####------- -------------#------- -------#######--- #######

April 12, 2006, SOUTHERN GREECE, MW=5.7 Natasha Maternovskaya CENTROID, MOMENT TENSOR SOLUTION HARVARD EVENT-FILE NAME C041206B DATA USED: GSN L.P. BODY WAVES: 56S,111C, T= 40 SURFACE WAVES: 56S,115C, T= 50 CENTROID LOCATION: ORIGIN TIME 16:52: 7.2 0.2 LAT 37.62N 0.02;LON 20.76E 0.02 DEP 20.5 0.8;HALF-DURATION 1.7 MOMENT TENSOR; SCALE 10**24 D-CM MRR= 2.37 0.07; MTT= 0.11 0.05 MPP=-2.48 0.06; MRT= 1.79 0.14 MRP=-2.46 0.16; MTP= 0.76 0.05 PRINCIPAL AXES: 1.(T) VAL= 3.92;PLG=62;AZM= 40 2.(N) 0.09; 12; 153 3.(P) -4.01; 25; 248 BEST DOUBLE COUPLE:M0=4.0*10**24 NP2:STRIKE=149;DIP=71;SLIP= 78 #########-- -###############--- ---#################--- -----##################---- -------##################---- --------########## ######---- ---------######### T #######--- -----------######## #######---- ------------#################---- -------------################---- --- --------###############---- -- P ---------##############--- -- ----------############---- ----------------#########---- ----------------#######---- -----------------###--- ---------------##-- --------###

Date 6 4 12 Time 16 52 2.1 Loc 37.71 20.91 18. Dur 9.0 SED http://www.seismo.ethz.ch/mt/armt/all_armt.html ScMom 0.466E+25 Mw 5.72 MT 0.236E+25 0.425E+24 -0.279E+25 0.220E+25 -0.312E+25 0.620E+24 Err 0.573E+23 0.324E+23 0.456E+23 0.674E+23 0.752E+23 0.315E+23 Principal Axes: T - val 0.460E+01 plg 58 azi 39 N - 0.131E+00 13 153 P - -0.473E+01 27 250 Best Double Couple: NP1 - str 11 dip 21 slp 130 NP2 - 148 73 75 Isotropic component 0.000 Deviation from Double Couple 0.028 Freq range 0.0100 0.020 ****####*- ############*#*- --*##############*-- -----*##############**-- ------*################*-- --------*####### #####*--- --------*####### t ######*-- ----------*###### ######*--- -----------*##############*--- ------------*#############*--- --- -------*############*--- -- p --------*##########*--- -- ---------**########*--- ---------------*#####**--- ---------------* *#--- -------------- n #-- -----------# # -----#****

Deviatoric Moment Tensor Solution

The following broadband stations were used for the source inversion: ALLY ARU BILL COLD DBIC EKS2 KBK KSU1 KURK LBTB LSA LSZ OXF SUMG ULHL ULN WRPS YAK

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

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   20.0  167.   87.  138.   5.63     0.002 0.254E-05     0.361     0.044 0.107E-06  38.8

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