2010/06/20 23:13:54 43.805 17.021 33.0 4.40 Bosnia
USGS Felt map for this earthquake
USGS/SLU Moment Tensor Solution
ENS 2010/06/20 23:13:54:9 43.81 17.02 33.0 4.4 Bosnia
Stations used:
CH.FUORN CZ.KHC GE.MORC GE.PSZ GE.RUE GE.STU GR.CLL II.BFO
IU.GRFO MN.CUC MN.TIR MN.TRI PL.OJC
Filtering commands used:
hp c 0.01 n 3
lp c 0.04 n 3
Best Fitting Double Couple
Mo = 2.04e+22 dyne-cm
Mw = 4.14
Z = 25 km
Plane Strike Dip Rake
NP1 322 69 148
NP2 65 60 25
Principal Axes:
Axis Value Plunge Azimuth
T 2.04e+22 38 281
N 0.00e+00 52 112
P -2.04e+22 5 15
Moment Tensor: (dyne-cm)
Component Value
Mxx -1.84e+22
Mxy -7.44e+21
Mxz 1.22e+15
Myy 1.09e+22
Myz -1.02e+22
Mzz 7.47e+21
---------- P -
-------------- -----
###-------------------------
########----------------------
#############---------------------
################--------------------
###################-------------------
######################----------------##
###### ##############--------------###
####### T ################-----------#####
####### #################--------#######
############################-----#########
#############################--###########
###########################--###########
########################------##########
###################-----------########
-----####---------------------######
-----------------------------#####
----------------------------##
---------------------------#
----------------------
--------------
Global CMT Convention Moment Tensor:
R T P
7.47e+21 1.22e+15 1.02e+22
1.22e+15 -1.84e+22 7.44e+21
1.02e+22 7.44e+21 1.09e+22
Details of the solution is found at
http://www.eas.slu.edu/Earthquake_Center/MECH.NA/20100620231354/index.html
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STK = 65
DIP = 60
RAKE = 25
MW = 4.14
HS = 25.0
The waveform inversion is preferred.
The following compares this source inversion to others
USGS/SLU Moment Tensor Solution
ENS 2010/06/20 23:13:54:9 43.81 17.02 33.0 4.4 Bosnia
Stations used:
CH.FUORN CZ.KHC GE.MORC GE.PSZ GE.RUE GE.STU GR.CLL II.BFO
IU.GRFO MN.CUC MN.TIR MN.TRI PL.OJC
Filtering commands used:
hp c 0.01 n 3
lp c 0.04 n 3
Best Fitting Double Couple
Mo = 2.04e+22 dyne-cm
Mw = 4.14
Z = 25 km
Plane Strike Dip Rake
NP1 322 69 148
NP2 65 60 25
Principal Axes:
Axis Value Plunge Azimuth
T 2.04e+22 38 281
N 0.00e+00 52 112
P -2.04e+22 5 15
Moment Tensor: (dyne-cm)
Component Value
Mxx -1.84e+22
Mxy -7.44e+21
Mxz 1.22e+15
Myy 1.09e+22
Myz -1.02e+22
Mzz 7.47e+21
---------- P -
-------------- -----
###-------------------------
########----------------------
#############---------------------
################--------------------
###################-------------------
######################----------------##
###### ##############--------------###
####### T ################-----------#####
####### #################--------#######
############################-----#########
#############################--###########
###########################--###########
########################------##########
###################-----------########
-----####---------------------######
-----------------------------#####
----------------------------##
---------------------------#
----------------------
--------------
Global CMT Convention Moment Tensor:
R T P
7.47e+21 1.22e+15 1.02e+22
1.22e+15 -1.84e+22 7.44e+21
1.02e+22 7.44e+21 1.09e+22
Details of the solution is found at
http://www.eas.slu.edu/Earthquake_Center/MECH.NA/20100620231354/index.html
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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 0.01 n 3 lp c 0.04 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 75 -30 3.84 0.1772
WVFGRD96 1.0 55 75 -15 3.83 0.1834
WVFGRD96 2.0 235 75 -20 3.88 0.2042
WVFGRD96 3.0 60 85 0 3.89 0.2132
WVFGRD96 4.0 60 85 0 3.91 0.2196
WVFGRD96 5.0 65 70 20 3.96 0.2240
WVFGRD96 6.0 65 70 25 3.98 0.2293
WVFGRD96 7.0 65 70 25 3.99 0.2332
WVFGRD96 8.0 65 70 30 4.02 0.2365
WVFGRD96 9.0 240 90 -30 4.01 0.2368
WVFGRD96 10.0 240 90 -30 4.02 0.2396
WVFGRD96 11.0 240 90 -30 4.03 0.2417
WVFGRD96 12.0 60 90 30 4.03 0.2450
WVFGRD96 13.0 235 80 -30 4.04 0.2492
WVFGRD96 14.0 60 90 30 4.05 0.2511
WVFGRD96 15.0 235 80 -30 4.05 0.2547
WVFGRD96 16.0 60 90 30 4.06 0.2561
WVFGRD96 17.0 60 90 25 4.07 0.2585
WVFGRD96 18.0 240 85 -25 4.08 0.2608
WVFGRD96 19.0 65 60 30 4.10 0.2624
WVFGRD96 20.0 65 60 30 4.10 0.2648
WVFGRD96 21.0 65 60 30 4.11 0.2673
WVFGRD96 22.0 65 60 25 4.12 0.2688
WVFGRD96 23.0 65 60 25 4.13 0.2701
WVFGRD96 24.0 65 60 25 4.14 0.2704
WVFGRD96 25.0 65 60 25 4.14 0.2705
WVFGRD96 26.0 65 60 25 4.15 0.2699
WVFGRD96 27.0 60 65 20 4.15 0.2696
WVFGRD96 28.0 60 65 20 4.15 0.2690
WVFGRD96 29.0 60 65 20 4.16 0.2681
The best solution is
WVFGRD96 25.0 65 60 25 4.14 0.2705
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 0.01 n 3 lp c 0.04 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. |
Should the national backbone of the USGS Advanced National Seismic System (ANSS) be implemented with an interstation separation of 300 km, it is very likely that an earthquake such as this would have been recorded at distances on the order of 100-200 km. This means that the closest station would have information on source depth and mechanism that was lacking here.
Dr. Harley Benz, USGS, provided the USGS USNSN digital data. The digital data used in this study were provided by Natural Resources Canada through their AUTODRM site http://www.seismo.nrcan.gc.ca/nwfa/autodrm/autodrm_req_e.php, and IRIS using their BUD interface.
Thanks also to the many seismic network operators whose dedication make this effort possible: University of Alaska, University of Washington, Oregon State University, University of Utah, Montana Bureas of Mines, UC Berkely, Caltech, UC San Diego, Saint L ouis University, Universityof Memphis, Lamont Doehrty Earth Observatory, Boston College, the Iris stations and the Transportable Array of EarthScope.
The 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=Mon Jun 21 00:47:36 MDT 2010