2009/02/01 10:27:17 40.4900 42.3290 3.5 4.60 Senkaya, Turkey
USGS Felt map for this earthquake
USGS/SLU Moment Tensor Solution
ENS 2009/02/01 10:27:17:0 40.49 42.33 3.5 4.6 Senkaya, Turkey
Stations used:
KO.AGRB KO.BCA KO.CLDR KO.CORM KO.CUKT KO.ESPY KO.GAZ
KO.KARS KO.KOZT KO.KTUT KO.PTK KO.PZAR KO.URFA KO.VANB
Filtering commands used:
hp c 0.02 n 3
lp c 0.05 n 3
Best Fitting Double Couple
Mo = 4.22e+22 dyne-cm
Mw = 4.35
Z = 14 km
Plane Strike Dip Rake
NP1 65 75 20
NP2 330 71 164
Principal Axes:
Axis Value Plunge Azimuth
T 4.22e+22 25 288
N 0.00e+00 65 100
P -4.22e+22 3 197
Moment Tensor: (dyne-cm)
Component Value
Mxx -3.52e+22
Mxy -2.18e+22
Mxz 6.99e+21
Myy 2.80e+22
Myz -1.46e+22
Mzz 7.21e+21
--------------
#---------------------
#######---------------------
##########--------------------
##############--------------------
#################-------------------
###################------------------#
### ################---------------###
### T #################------------#####
#### ##################--------#########
##########################-----###########
###########################-##############
########################----##############
###################---------############
##############--------------############
######----------------------##########
----------------------------########
---------------------------#######
-------------------------#####
-------------------------###
---- ---------------
P -----------
Global CMT Convention Moment Tensor:
R T P
7.21e+21 6.99e+21 1.46e+22
6.99e+21 -3.52e+22 2.18e+22
1.46e+22 2.18e+22 2.80e+22
Details of the solution is found at
http://www.eas.slu.edu/Earthquake_Center/MECH.NA/20090201102717/index.html
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STK = 65
DIP = 75
RAKE = 20
MW = 4.35
HS = 14.0
The waveform inversion is preferred.
The following compares this source inversion to others
USGS/SLU Moment Tensor Solution
ENS 2009/02/01 10:27:17:0 40.49 42.33 3.5 4.6 Senkaya, Turkey
Stations used:
KO.AGRB KO.BCA KO.CLDR KO.CORM KO.CUKT KO.ESPY KO.GAZ
KO.KARS KO.KOZT KO.KTUT KO.PTK KO.PZAR KO.URFA KO.VANB
Filtering commands used:
hp c 0.02 n 3
lp c 0.05 n 3
Best Fitting Double Couple
Mo = 4.22e+22 dyne-cm
Mw = 4.35
Z = 14 km
Plane Strike Dip Rake
NP1 65 75 20
NP2 330 71 164
Principal Axes:
Axis Value Plunge Azimuth
T 4.22e+22 25 288
N 0.00e+00 65 100
P -4.22e+22 3 197
Moment Tensor: (dyne-cm)
Component Value
Mxx -3.52e+22
Mxy -2.18e+22
Mxz 6.99e+21
Myy 2.80e+22
Myz -1.46e+22
Mzz 7.21e+21
--------------
#---------------------
#######---------------------
##########--------------------
##############--------------------
#################-------------------
###################------------------#
### ################---------------###
### T #################------------#####
#### ##################--------#########
##########################-----###########
###########################-##############
########################----##############
###################---------############
##############--------------############
######----------------------##########
----------------------------########
---------------------------#######
-------------------------#####
-------------------------###
---- ---------------
P -----------
Global CMT Convention Moment Tensor:
R T P
7.21e+21 6.99e+21 1.46e+22
6.99e+21 -3.52e+22 2.18e+22
1.46e+22 2.18e+22 2.80e+22
Details of the solution is found at
http://www.eas.slu.edu/Earthquake_Center/MECH.NA/20090201102717/index.html
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USGS/SLU Regional Moment Tensor Solution
09/02/01 10:27:16
EASTERN TURKEY
Epicenter: 40.490 42.330
MW 4.3
USGS/SLU REGIONAL MOMENT TENSOR
Depth 9 No. of sta: 3
Moment Tensor; Scale 10**15 Nm
Mrr= 0.27 Mtt=-2.75
Mpp= 2.48 Mrt= 0.39
Mrp= 0.82 Mtp= 1.35
Principal axes:
T Val= 3.09 Plg=17 Azm=284
N 0.00 72 92
P -3.09 3 193
Best Double Couple:Mo=3.1*10**15
NP1:Strike= 60 Dip=80 Slip= 15
NP2: 327 75 170
-------
-----------------
###------------------
#######------------------
###########------------------
##############---------------##
# ###########------------####
## T ############---------#######
## ##############----##########
#################################
#################----############
##############--------###########
#########-------------#########
####-------------------########
----------------------#######
---------------------####
-------------------##
--- -----------
P ------
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The focal mechanism was determined using broadband seismic waveforms. The location of the event and the and stations used for the waveform inversion are shown in the next figure.
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The program wvfgrd96 was used with good traces observed at short distance to determine the focal mechanism, depth and seismic moment. This technique requires a high quality signal and well determined velocity model for the Green functions. To the extent that these are the quality data, this type of mechanism should be preferred over the radiation pattern technique which requires the separate step of defining the pressure and tension quadrants and the correct strike.
The observed and predicted traces are filtered using the following gsac commands:
hp c 0.02 n 3 lp c 0.05 n 3The results of this grid search from 0.5 to 19 km depth are as follow:
DEPTH STK DIP RAKE MW FIT
WVFGRD96 0.5 50 80 15 4.01 0.2705
WVFGRD96 1.0 50 85 10 4.03 0.2927
WVFGRD96 2.0 50 85 10 4.12 0.3752
WVFGRD96 3.0 50 80 10 4.16 0.4039
WVFGRD96 4.0 55 75 20 4.20 0.4267
WVFGRD96 5.0 55 75 20 4.22 0.4482
WVFGRD96 6.0 60 75 25 4.24 0.4699
WVFGRD96 7.0 60 75 20 4.26 0.4927
WVFGRD96 8.0 60 75 25 4.29 0.5136
WVFGRD96 9.0 60 75 25 4.31 0.5265
WVFGRD96 10.0 60 75 25 4.32 0.5358
WVFGRD96 11.0 60 75 20 4.32 0.5424
WVFGRD96 12.0 65 75 20 4.33 0.5472
WVFGRD96 13.0 65 75 20 4.34 0.5508
WVFGRD96 14.0 65 75 20 4.35 0.5513
WVFGRD96 15.0 65 75 15 4.35 0.5512
WVFGRD96 16.0 65 80 15 4.36 0.5494
WVFGRD96 17.0 65 80 15 4.37 0.5476
WVFGRD96 18.0 235 75 -15 4.39 0.5435
WVFGRD96 19.0 235 75 -15 4.39 0.5410
WVFGRD96 20.0 235 75 -15 4.40 0.5377
WVFGRD96 21.0 235 75 -15 4.41 0.5335
WVFGRD96 22.0 235 75 -15 4.41 0.5283
WVFGRD96 23.0 235 75 -15 4.42 0.5229
WVFGRD96 24.0 235 75 -15 4.42 0.5169
WVFGRD96 25.0 235 75 -15 4.43 0.5104
WVFGRD96 26.0 235 75 -15 4.44 0.5037
WVFGRD96 27.0 235 75 -15 4.44 0.4963
WVFGRD96 28.0 235 80 -10 4.45 0.4892
WVFGRD96 29.0 235 80 -10 4.45 0.4821
The best solution is
WVFGRD96 14.0 65 75 20 4.35 0.5513
The mechanism correspond to the best fit is
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The best fit as a function of depth is given in the following figure:
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The comparison of the observed and predicted waveforms is given in the next figure. The red traces are the observed and the blue are the predicted. Each observed-predicted componnet is plotted to the same scale and peak amplitudes are indicated by the numbers to the left of each trace. The number in black at the rightr of each predicted traces it the time shift required for maximum correlation between the observed and predicted traces. This time shift is required because the synthetics are not computed at exactly the same distance as the observed and because the velocity model used in the predictions may not be perfect. A positive time shift indicates that the prediction is too fast and should be delayed to match the observed trace (shift to the right in this figure). A negative value indicates that the prediction is too slow. The bandpass filter used in the processing and for the display was
hp c 0.02 n 3 lp c 0.05 n 3
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| Focal mechanism sensitivity at the preferred depth. The red color indicates a very good fit to thewavefroms. Each solution is plotted as a vector at a given value of strike and dip with the angle of the vector representing the rake angle, measured, with respect to the upward vertical (N) in the figure. |
The WUS used for the waveform synthetic seismograms and for the surface wave eigenfunctions and dispersion is as follows:
MODEL.01
Model after 8 iterations
ISOTROPIC
KGS
FLAT EARTH
1-D
CONSTANT VELOCITY
LINE08
LINE09
LINE10
LINE11
H(KM) VP(KM/S) VS(KM/S) RHO(GM/CC) QP QS ETAP ETAS FREFP FREFS
1.9000 3.4065 2.0089 2.2150 0.302E-02 0.679E-02 0.00 0.00 1.00 1.00
6.1000 5.5445 3.2953 2.6089 0.349E-02 0.784E-02 0.00 0.00 1.00 1.00
13.0000 6.2708 3.7396 2.7812 0.212E-02 0.476E-02 0.00 0.00 1.00 1.00
19.0000 6.4075 3.7680 2.8223 0.111E-02 0.249E-02 0.00 0.00 1.00 1.00
0.0000 7.9000 4.6200 3.2760 0.164E-10 0.370E-10 0.00 0.00 1.00 1.00
Here we tabulate the reasons for not using certain digital data sets
The following stations did not have a valid response files:
DATE=Sun Feb 1 20:36:06 CST 2009