USGS/SLU Moment Tensor Solution
ENS 2021/08/13 11:57:35:0 35.88 -84.90 0.0 3.0 Tennessee
Stations used:
CO.CASEE CO.HODGE CO.PAULI ET.CPCT IM.TKL IU.WCI IU.WVT
N4.R49A N4.R50A N4.S51A N4.T47A N4.T50A N4.U49A N4.V48A
N4.V53A N4.V55A N4.W50A N4.W52A N4.X48A N4.X51A N4.Y52A
NM.BLO NM.USIN US.GOGA US.LRAL US.TZTN
Filtering commands used:
cut o DIST/3.3 -20 o DIST/3.3 +50
rtr
taper w 0.1
hp c 0.03 n 3
lp c 0.10 n 3
Best Fitting Double Couple
Mo = 1.35e+22 dyne-cm
Mw = 4.02
Z = 1 km
Plane Strike Dip Rake
NP1 290 75 -90
NP2 110 15 -90
Principal Axes:
Axis Value Plunge Azimuth
T 1.35e+22 30 20
N 0.00e+00 -0 290
P -1.35e+22 60 200
Moment Tensor: (dyne-cm)
Component Value
Mxx 5.96e+21
Mxy 2.17e+21
Mxz 1.10e+22
Myy 7.89e+20
Myz 4.00e+21
Mzz -6.74e+21
##############
######################
################# ########
################## T #########
#################### ###########
####################################
######################################
-----------#############################
------------------######################
#-----------------------##################
#----------------------------#############
#-------------------------------##########
##---------------------------------#######
#--------------- ------------------###
##-------------- P --------------------#
##------------- --------------------
###---------------------------------
###------------------------------#
###--------------------------#
#####--------------------###
########---------#####
##############
Global CMT Convention Moment Tensor:
R T P
-6.74e+21 1.10e+22 -4.00e+21
1.10e+22 5.96e+21 -2.17e+21
-4.00e+21 -2.17e+21 7.89e+20
Details of the solution is found at
http://www.eas.slu.edu/eqc/eqc_mt/MECH.NA/20210813115735/index.html
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STK = 110
DIP = 15
RAKE = -90
MW = 4.02
HS = 1.0
The NDK file is 20210813115735.ndk The waveform inversion is preferred.
The following compares this source inversion to others
USGS/SLU Moment Tensor Solution
ENS 2021/08/13 11:57:35:0 35.88 -84.90 0.0 3.0 Tennessee
Stations used:
CO.CASEE CO.HODGE CO.PAULI ET.CPCT IM.TKL IU.WCI IU.WVT
N4.R49A N4.R50A N4.S51A N4.T47A N4.T50A N4.U49A N4.V48A
N4.V53A N4.V55A N4.W50A N4.W52A N4.X48A N4.X51A N4.Y52A
NM.BLO NM.USIN US.GOGA US.LRAL US.TZTN
Filtering commands used:
cut o DIST/3.3 -20 o DIST/3.3 +50
rtr
taper w 0.1
hp c 0.03 n 3
lp c 0.10 n 3
Best Fitting Double Couple
Mo = 1.35e+22 dyne-cm
Mw = 4.02
Z = 1 km
Plane Strike Dip Rake
NP1 290 75 -90
NP2 110 15 -90
Principal Axes:
Axis Value Plunge Azimuth
T 1.35e+22 30 20
N 0.00e+00 -0 290
P -1.35e+22 60 200
Moment Tensor: (dyne-cm)
Component Value
Mxx 5.96e+21
Mxy 2.17e+21
Mxz 1.10e+22
Myy 7.89e+20
Myz 4.00e+21
Mzz -6.74e+21
##############
######################
################# ########
################## T #########
#################### ###########
####################################
######################################
-----------#############################
------------------######################
#-----------------------##################
#----------------------------#############
#-------------------------------##########
##---------------------------------#######
#--------------- ------------------###
##-------------- P --------------------#
##------------- --------------------
###---------------------------------
###------------------------------#
###--------------------------#
#####--------------------###
########---------#####
##############
Global CMT Convention Moment Tensor:
R T P
-6.74e+21 1.10e+22 -4.00e+21
1.10e+22 5.96e+21 -2.17e+21
-4.00e+21 -2.17e+21 7.89e+20
Details of the solution is found at
http://www.eas.slu.edu/eqc/eqc_mt/MECH.NA/20210813115735/index.html
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Moment (dyne-cm) 1.27E+22 dyne-cm
Magnitude (Mw) 4.00
Principal Axes:
Axis Value Plunge Azimuth
T 1.27E+22 29. 19.
N -3.22E+14 1. 288.
P -1.27E+22 61. 197.
Moment Tensor: (dyne-cm) Aki-Richards
Component Value
Mxx 6.16E+21
Mxy 2.15E+21
Mxz 1.02E+22
Myy 7.46E+20
Myz 3.30E+21
Mzz -6.91E+21
Global CMT Convention Moment Tensor: (dyne-cm)
R T F
R -6.91E+21 1.02E+22 -3.30E+21
T 1.02E+22 6.16E+21 -2.15E+21
F -3.30E+21 -2.15E+21 7.46E+20
Moment (dyne-cm) 1.27E+22 dyne-cm
Magnitude (Mw) 4.00
Principal Axes:
Axis Value Plunge Azimuth
T 1.27E+22 29. 19.
N -3.22E+14 1. 288.
P -1.27E+22 61. 197.
Moment Tensor: (dyne-cm) Aki-Richards Lune parameters
Component Value
Mxx 6.16E+21 beta: 90.00
Mxy 2.15E+21 gamma: 0.00
Mxy 2.15E+21
Mxz 1.02E+22
Myy 7.46E+20
Myz 3.30E+21
Mzz -6.91E+21
############## :
###################### :---:
################# ######## ::. ..::
################## T ######### :--------:
#################### ########### :: . . . :
#################################### : . . . :
###################################### :------------::
-----------############################# :: . . . :
-------------------##################### : . . . :
#-------------------------################ :---------------:
#-----------------------------############ : . . . :
#---------------------------------######## :=======#=======:
##----------------------------------###### : . . . :
##-------------- -------------------## : . . . :
##-------------- P --------------------- :---------------:
###------------ -------------------- : . . . :
###--------------------------------# :: . . . :
####-----------------------------# :------------::
####-------------------------# : . . . :
######------------------#### :: . . . :
#########-------###### :--------:
############## ::. ..::
:---:
:
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Moment (dyne-cm) 1.36E+22 dyne-cm
Magnitude (Mw) 4.02
Principal Axes:
Axis Value Plunge Azimuth
T 1.36E+22 30. 20.
N 2.60E+18 0. 290.
P -1.36E+22 60. 200.
Moment Tensor: (dyne-cm) Aki-Richards
Component Value
Mxx 6.00E+21
Mxy 2.18E+21
Mxz 1.11E+22
Myy 7.95E+20
Myz 4.02E+21
Mzz -6.79E+21
Global CMT Convention Moment Tensor: (dyne-cm)
R T F
R -6.79E+21 1.11E+22 -4.02E+21
T 1.11E+22 6.00E+21 -2.18E+21
F -4.02E+21 -2.18E+21 7.95E+20
Moment (dyne-cm) 1.36E+22 dyne-cm
Magnitude (Mw) 4.02
Principal Axes:
Axis Value Plunge Azimuth
T 1.36E+22 30. 20.
N 2.60E+18 0. 290.
P -1.36E+22 60. 200.
Moment Tensor: (dyne-cm) Aki-Richards Lune parameters
Component Value
Mxx 6.00E+21 beta: 89.99
Mxy 2.18E+21 gamma: 0.00
Mxy 2.18E+21
Mxz 1.11E+22
Myy 7.95E+20
Myz 4.02E+21
Mzz -6.79E+21
############## :
###################### :---:
################# ######## ::. ..::
################## T ######### :--------:
#################### ########### :: . . . :
#################################### : . . . :
###################################### :------------::
-----------############################# :: . . . :
------------------###################### : . . . :
#-----------------------################## :---------------:
#----------------------------############# : . . . :
#-------------------------------########## :=======#=======:
##---------------------------------####### : . . . :
#--------------- ------------------### : . . . :
##-------------- P --------------------# :---------------:
##------------- -------------------- : . . . :
###--------------------------------- :: . . . :
###------------------------------# :------------::
###--------------------------# : . . . :
#####--------------------### :: . . . :
#######----------##### :--------:
############## ::. ..::
:---:
:
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Moment (dyne-cm) 1.36E+22 dyne-cm
Magnitude (Mw) 4.02
Principal Axes:
Axis Value Plunge Azimuth
T 1.36E+22 30. 20.
N 2.60E+18 0. 290.
P -1.36E+22 60. 200.
Moment Tensor: (dyne-cm) Aki-Richards
Component Value
Mxx 6.00E+21
Mxy 2.18E+21
Mxz 1.11E+22
Myy 7.95E+20
Myz 4.02E+21
Mzz -6.79E+21
Global CMT Convention Moment Tensor: (dyne-cm)
R T F
R -6.79E+21 1.11E+22 -4.02E+21
T 1.11E+22 6.00E+21 -2.18E+21
F -4.02E+21 -2.18E+21 7.95E+20
Moment (dyne-cm) 1.36E+22 dyne-cm
Magnitude (Mw) 4.02
Principal Axes:
Axis Value Plunge Azimuth
T 1.36E+22 30. 20.
N 2.60E+18 0. 290.
P -1.36E+22 60. 200.
Moment Tensor: (dyne-cm) Aki-Richards Lune parameters
Component Value
Mxx 6.00E+21 beta: 89.99
Mxy 2.18E+21 gamma: 0.00
Mxy 2.18E+21
Mxz 1.11E+22
Myy 7.95E+20
Myz 4.02E+21
Mzz -6.79E+21
############## :
###################### :---:
################# ######## ::. ..::
################## T ######### :--------:
#################### ########### :: . . . :
#################################### : . . . :
###################################### :------------::
-----------############################# :: . . . :
------------------###################### : . . . :
#-----------------------################## :---------------:
#----------------------------############# : . . . :
#-------------------------------########## :=======#=======:
##---------------------------------####### : . . . :
#--------------- ------------------### : . . . :
##-------------- P --------------------# :---------------:
##------------- -------------------- : . . . :
###--------------------------------- :: . . . :
###------------------------------# :------------::
###--------------------------# : . . . :
#####--------------------### :: . . . :
#######----------##### :--------:
############## ::. ..::
:---:
:
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Moment (dyne-cm) 1.27E+22 dyne-cm
Magnitude (Mw) 4.00
Principal Axes:
Axis Value Plunge Azimuth
T 1.37E+22 30. 20.
N 1.32E+20 0. 290.
P -1.16E+22 60. 200.
Moment Tensor: (dyne-cm) Aki-Richards
Component Value
Mxx 6.48E+21
Mxy 2.31E+21
Mxz 1.03E+22
Myy 9.73E+20
Myz 3.74E+21
Mzz -5.31E+21
Global CMT Convention Moment Tensor: (dyne-cm)
R T F
R -5.31E+21 1.03E+22 -3.74E+21
T 1.03E+22 6.48E+21 -2.31E+21
F -3.74E+21 -2.31E+21 9.73E+20
Moment (dyne-cm) 1.27E+22 dyne-cm
Magnitude (Mw) 4.00
Principal Axes:
Axis Value Plunge Azimuth
T 1.37E+22 30. 20.
N 1.32E+20 0. 290.
P -1.16E+22 60. 200.
Moment Tensor: (dyne-cm) Aki-Richards Lune parameters
Component Value
Mxx 6.48E+21 beta: 86.05
Mxy 2.31E+21 gamma: -2.28
Mxy 2.31E+21
Mxz 1.03E+22
Myy 9.73E+20
Myz 3.74E+21
Mzz -5.31E+21
############## :
###################### :---:
################# ######## ::. ..::
################## T ######### :--------:
#################### ########### :: . . . :
#################################### : . . . :
###################################### :------------::
##------################################ :: . . . :
#---------------######################## : . . . :
#----------------------################### :---------------:
#--------------------------############### : . . . :
##-----------------------------########### :======#========:
##--------------------------------######## : . . . :
##-------------- -----------------#### : . . . :
###------------- P -------------------## :---------------:
###------------ -------------------# : . . . :
###--------------------------------# :: . . . :
####----------------------------## :------------::
####------------------------## : . . . :
######------------------#### :: . . . :
###########---######## :--------:
############## ::. ..::
:---:
:
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Moment (dyne-cm) 1.27E+22 dyne-cm
Magnitude (Mw) 4.00
Principal Axes:
Axis Value Plunge Azimuth
T 1.27E+22 29. 19.
N 7.51E+13 1. 288.
P -1.27E+22 61. 197.
Moment Tensor: (dyne-cm) Aki-Richards
Component Value
Mxx 6.16E+21
Mxy 2.15E+21
Mxz 1.02E+22
Myy 7.46E+20
Myz 3.30E+21
Mzz -6.91E+21
Global CMT Convention Moment Tensor: (dyne-cm)
R T F
R -6.91E+21 1.02E+22 -3.30E+21
T 1.02E+22 6.16E+21 -2.15E+21
F -3.30E+21 -2.15E+21 7.46E+20
Moment (dyne-cm) 1.27E+22 dyne-cm
Magnitude (Mw) 4.00
Principal Axes:
Axis Value Plunge Azimuth
T 1.27E+22 29. 19.
N 7.51E+13 1. 288.
P -1.27E+22 61. 197.
Moment Tensor: (dyne-cm) Aki-Richards Lune parameters
Component Value
Mxx 6.16E+21 beta: 90.00
Mxy 2.15E+21 gamma: 0.00
Mxy 2.15E+21
Mxz 1.02E+22
Myy 7.46E+20
Myz 3.30E+21
Mzz -6.91E+21
############## :
###################### :---:
################# ######## ::. ..::
################## T ######### :--------:
#################### ########### :: . . . :
#################################### : . . . :
###################################### :------------::
-----------############################# :: . . . :
-------------------##################### : . . . :
#-------------------------################ :---------------:
#-----------------------------############ : . . . :
#---------------------------------######## :=======#=======:
##----------------------------------###### : . . . :
##-------------- -------------------## : . . . :
##-------------- P --------------------- :---------------:
###------------ -------------------- : . . . :
###--------------------------------# :: . . . :
####-----------------------------# :------------::
####-------------------------# : . . . :
######------------------#### :: . . . :
#########-------###### :--------:
############## ::. ..::
:---:
:
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Moment (dyne-cm) 1.27E+22 dyne-cm
Magnitude (Mw) 4.00
Principal Axes:
Axis Value Plunge Azimuth
T 1.27E+22 29. 19.
N -8.35E+14 1. 288.
P -1.27E+22 61. 197.
Moment Tensor: (dyne-cm) Aki-Richards
Component Value
Mxx 6.16E+21
Mxy 2.15E+21
Mxz 1.02E+22
Myy 7.46E+20
Myz 3.30E+21
Mzz -6.91E+21
Global CMT Convention Moment Tensor: (dyne-cm)
R T F
R -6.91E+21 1.02E+22 -3.30E+21
T 1.02E+22 6.16E+21 -2.15E+21
F -3.30E+21 -2.15E+21 7.46E+20
Moment (dyne-cm) 1.27E+22 dyne-cm
Magnitude (Mw) 4.00
Principal Axes:
Axis Value Plunge Azimuth
T 1.27E+22 29. 19.
N -8.35E+14 1. 288.
P -1.27E+22 61. 197.
Moment Tensor: (dyne-cm) Aki-Richards Lune parameters
Component Value
Mxx 6.16E+21 beta: 90.00
Mxy 2.15E+21 gamma: 0.00
Mxy 2.15E+21
Mxz 1.02E+22
Myy 7.46E+20
Myz 3.30E+21
Mzz -6.91E+21
############## :
###################### :---:
################# ######## ::. ..::
################## 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:
cut o DIST/3.3 -20 o DIST/3.3 +50 rtr taper w 0.1 hp c 0.03 n 3 lp c 0.10 n 3The results of this grid search from 0.5 to 19 km depth are as follow:
DEPTH STK DIP RAKE MW FIT
WVFGRD96 1.0 110 15 -90 4.02 0.9978
WVFGRD96 2.0 290 65 -90 3.96 0.9242
WVFGRD96 3.0 105 25 -95 3.93 0.7786
WVFGRD96 4.0 110 70 -85 3.88 0.6722
WVFGRD96 5.0 280 20 -100 3.85 0.6352
WVFGRD96 6.0 110 70 -85 3.84 0.6130
WVFGRD96 7.0 110 75 -85 3.82 0.6030
WVFGRD96 8.0 345 60 40 3.84 0.5963
WVFGRD96 9.0 345 60 40 3.84 0.6037
WVFGRD96 10.0 115 80 -75 3.85 0.5902
WVFGRD96 11.0 105 20 85 3.85 0.5826
WVFGRD96 12.0 290 70 90 3.86 0.5888
WVFGRD96 13.0 105 20 85 3.87 0.5912
WVFGRD96 14.0 110 25 90 3.88 0.5912
WVFGRD96 15.0 110 25 90 3.89 0.5888
WVFGRD96 16.0 110 25 90 3.89 0.5840
WVFGRD96 17.0 290 60 90 3.91 0.5781
WVFGRD96 18.0 110 30 90 3.92 0.5707
WVFGRD96 19.0 290 60 90 3.93 0.5613
WVFGRD96 20.0 290 60 90 3.95 0.5458
WVFGRD96 21.0 290 60 90 3.96 0.5368
WVFGRD96 22.0 115 30 95 3.97 0.5265
WVFGRD96 23.0 115 35 95 3.98 0.5152
WVFGRD96 24.0 115 35 95 3.99 0.5027
WVFGRD96 25.0 115 35 95 3.99 0.4886
WVFGRD96 26.0 115 90 80 4.01 0.4819
WVFGRD96 27.0 120 85 80 4.03 0.4743
WVFGRD96 28.0 120 85 80 4.04 0.4656
WVFGRD96 29.0 120 85 80 4.04 0.4561
The best solution is
WVFGRD96 1.0 110 15 -90 4.02 0.9978
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 component is plotted to the same scale and peak amplitudes are indicated by the numbers to the left of each trace. A pair of numbers is given in black at the right of each predicted traces. The upper number 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 lower number gives the percentage of variance reduction to characterize the individual goodness of fit (100% indicates a perfect fit).
The bandpass filter used in the processing and for the display was
cut o DIST/3.3 -20 o DIST/3.3 +50 rtr taper w 0.1 hp c 0.03 n 3 lp c 0.10 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. |
A check on the assumed source location is possible by looking at the time shifts between the observed and predicted traces. The time shifts for waveform matching arise for several reasons:
Time_shift = A + B cos Azimuth + C Sin Azimuth
The time shifts for this inversion lead to the next figure:
The derived shift in origin time and epicentral coordinates are given at the bottom of the figure.
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 wvfmtd96 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:
cut o DIST/3.3 -20 o DIST/3.3 +50 rtr taper w 0.1 hp c 0.03 n 3 lp c 0.10 n 3The results of this grid search over depth are as follow:
MT Program H(km) STK DIP RAKE Mw Rvar StdErr Fit WtRvar WtStdErr Pclvd Mxx(dyne-cm) Myy Mxy Mxz Myz Mzz WVFMTD961 0.5 288. 77. -90. 4.02 0.988 0.158E-07 0.988 0.994 0.125E-07 4.0 0.5272953E+22 0.3828548E+21 0.1903535E+22 0.1146568E+23 0.3781525E+22 -0.5655808E+22 WVFMTD961 1.0 288. 74. -91. 4.00 1.000 0.171E-12 1.000 1.000 0.141E-12 0.0 0.6160384E+22 0.7464938E+21 0.2148202E+22 0.1017061E+23 0.3297875E+22 -0.6906877E+22 WVFMTD961 2.0 289. 62. -90. 3.97 0.931 0.384E-07 0.928 0.965 0.307E-07 15.6 0.7927731E+22 0.1786312E+22 0.2474400E+22 0.6031797E+22 0.2055521E+22 -0.9714043E+22 WVFMTD961 3.0 287. 63. -91. 3.93 0.785 0.682E-07 0.775 0.886 0.543E-07 9.2 0.7242831E+22 0.3429268E+21 0.2488077E+22 0.5558179E+22 0.1640367E+22 -0.7585757E+22 WVFMTD961 4.0 292. 71. -85. 3.84 0.641 0.884E-07 0.637 0.801 0.689E-07 77.3 0.4902474E+22 -0.2384569E+22 0.2626491E+22 0.4952387E+22 0.1817291E+22 -0.2517905E+22 WVFMTD961 5.0 163. 62. 45. 3.84 0.519 0.102E-06 0.543 0.721 0.765E-07 38.0 0.1549988E+22 -0.5488249E+22 0.2277796E+22 0.4095486E+22 0.2175244E+22 0.3938261E+22 WVFMTD961 6.0 168. 57. 53. 3.86 0.537 0.994E-07 0.567 0.735 0.743E-07 30.5 0.5811001E+21 -0.6263082E+22 0.2119343E+22 0.3747337E+22 0.1968597E+22 0.5681982E+22 WVFMTD961 7.0 171. 54. 58. 3.87 0.557 0.973E-07 0.590 0.750 0.724E-07 30.3 -0.5004246E+20 -0.6618708E+22 0.1920355E+22 0.3418862E+22 0.1753410E+22 0.6668751E+22 WVFMTD961 8.0 172. 53. 61. 3.87 0.572 0.956E-07 0.610 0.760 0.706E-07 34.1 -0.3245254E+21 -0.6693117E+22 0.1719968E+22 0.3372994E+22 0.1786633E+22 0.7017643E+22 WVFMTD961 9.0 173. 53. 63. 3.88 0.577 0.951E-07 0.619 0.764 0.697E-07 35.5 -0.6328949E+21 -0.6850955E+22 0.1638139E+22 0.3200347E+22 0.1761806E+22 0.7483849E+22 WVFMTD961 10.0 173. 52. 63. 3.90 0.578 0.949E-07 0.613 0.764 0.703E-07 44.1 -0.1037669E+22 -0.7230752E+22 0.1592521E+22 0.3679996E+22 0.1838325E+22 0.8268420E+22
The best solution is
WVFMTD961 1.0 288. 74. -91. 4.00 1.000 0.171E-12 1.000 1.000 0.141E-12 0.0 0.6160384E+22 0.7464938E+21 0.2148202E+22 0.1017061E+23 0.3297875E+22 -0.6906877E+22
The complete moment tensor decomposition using the program mtdinfo is given in the text file MTDinfo.txt. (Jost, M. L., and R. B. Herrmann (1989). A student's guide to and review of moment tensors, Seism. Res. Letters 60, 37-57. SRL_60_2_37-57.pdf.
The P-wave first motion mechanism corresponding to the best fit is
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The best fit as a function of depth is given in the following figure:
|
|
|
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 component is plotted to the same scale and peak amplitudes are indicated by the numbers to the left of each trace. A pair of numbers is given in black at the right of each predicted traces. The upper number 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 lower number gives the percentage of variance reduction to characterize the individual goodness of fit (100% indicates a perfect fit).
The bandpass filter used in the processing and for the display was
cut o DIST/3.3 -20 o DIST/3.3 +50 rtr taper w 0.1 hp c 0.03 n 3 lp c 0.10 n 3
|
|
|
A check on the assumed source location is possible by looking at the time shifts between the observed and predicted traces. The time shifts for waveform matching arise for several reasons:
Time_shift = A + B cos Azimuth + C Sin Azimuth
The time shifts for this inversion lead to the next figure:
The derived shift in origin time and epicentral coordinates are given at the bottom of the figure.
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.
|
|
|
The program wvfmt96 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:
cut o DIST/3.3 -20 o DIST/3.3 +50 rtr taper w 0.1 hp c 0.03 n 3 lp c 0.10 n 3The results of this grid search over depth are as follow:
MT Program H(km) STK DIP RAKE Mw Rvar StdErr Fit WtRvar WtStdErr Pclvd Mxx(dyne-cm) Myy Mxy Mxz Myz Mzz WVFMT961 0.5 288. 72. -90. 4.07 0.995 0.101E-07 0.995 0.998 0.802E-08 23.4 0.3060780E+22 -0.1828070E+22 0.1897817E+22 0.1143987E+23 0.3761120E+22 -0.1427752E+23 WVFMT961 1.0 288. 74. -91. 4.00 1.000 0.172E-12 1.000 1.000 0.141E-12 0.0 0.6160383E+22 0.7464929E+21 0.2148202E+22 0.1017061E+23 0.3297875E+22 -0.6906881E+22 WVFMT961 2.0 284. 72. -97. 3.94 0.974 0.235E-07 0.973 0.987 0.187E-07 81.2 0.1074636E+23 0.4410171E+22 0.2606550E+22 0.4636622E+22 0.1442445E+22 0.4562300E+22 WVFMT961 3.0 157. 73. 23. 3.98 0.945 0.342E-07 0.943 0.972 0.272E-07 98.0 0.1211826E+23 0.5537518E+22 0.2703538E+22 0.4192982E+22 0.1512036E+22 0.7083022E+22 WVFMT961 4.0 159. 70. 26. 4.02 0.901 0.460E-07 0.904 0.949 0.352E-07 62.7 0.1303720E+23 0.6519482E+22 0.2646221E+22 0.3571630E+22 0.1440815E+22 0.1043169E+23 WVFMT961 5.0 160. 68. 30. 4.04 0.856 0.554E-07 0.864 0.926 0.419E-07 49.4 0.1332522E+23 0.6986453E+22 0.2496727E+22 0.3363982E+22 0.1461905E+22 0.1186732E+23 WVFMT961 6.0 160. 68. 33. 4.05 0.825 0.611E-07 0.840 0.909 0.453E-07 49.9 0.1358383E+23 0.7413580E+22 0.2336442E+22 0.3453004E+22 0.1593278E+22 0.1268259E+23 WVFMT961 7.0 160. 67. 39. 4.06 0.780 0.686E-07 0.820 0.886 0.479E-07 38.2 0.1392622E+23 0.7750256E+22 0.2170132E+22 0.3315910E+22 0.1837872E+22 0.1425223E+23 WVFMT961 8.0 161. 65. 43. 4.07 0.745 0.737E-07 0.796 0.868 0.509E-07 34.6 0.1384003E+23 0.7775447E+22 0.2024126E+22 0.3255497E+22 0.1897881E+22 0.1492469E+23 WVFMT961 9.0 162. 64. 45. 4.07 0.720 0.773E-07 0.773 0.854 0.538E-07 33.0 0.1367604E+23 0.7675180E+22 0.1929001E+22 0.3228292E+22 0.1855703E+22 0.1526566E+23 WVFMT961 10.0 166. 58. 52. 4.09 0.693 0.810E-07 0.746 0.838 0.568E-07 34.1 0.1387097E+23 0.7844432E+22 0.1692200E+22 0.3406378E+22 0.1805838E+22 0.1789701E+23
The best solution is
WVFMT961 1.0 288. 74. -91. 4.00 1.000 0.172E-12 1.000 1.000 0.141E-12 0.0 0.6160383E+22 0.7464929E+21 0.2148202E+22 0.1017061E+23 0.3297875E+22 -0.6906881E+22
The complete moment tensor decomposition using the program mtinfo is given in the text file MTinfo.txt. (Jost, M. L., and R. B. Herrmann (1989). A student's guide to and review of moment tensors, Seism. Res. Letters 60, 37-57. SRL_60_2_37-57.pdf.
The P-wave first motion mechanism corresponding to the best fit is
|
|
|
The best fit as a function of depth is given in the following figure:
|
|
|
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 component is plotted to the same scale and peak amplitudes are indicated by the numbers to the left of each trace. A pair of numbers is given in black at the right of each predicted traces. The upper number 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 lower number gives the percentage of variance reduction to characterize the individual goodness of fit (100% indicates a perfect fit).
The bandpass filter used in the processing and for the display was
cut o DIST/3.3 -20 o DIST/3.3 +50 rtr taper w 0.1 hp c 0.03 n 3 lp c 0.10 n 3
|
|
|
A check on the assumed source location is possible by looking at the time shifts between the observed and predicted traces. The time shifts for waveform matching arise for several reasons:
Time_shift = A + B cos Azimuth + C Sin Azimuth
The time shifts for this inversion lead to the next figure:
The derived shift in origin time and epicentral coordinates are given at the bottom of the figure.
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.
|
|
|
The program wvfmtgrd96 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:
cut o DIST/3.3 -20 o DIST/3.3 +50 rtr taper w 0.1 hp c 0.03 n 3 lp c 0.10 n 3The results of this grid search over depth are as follow:
MT Program H(km) Mxx(dyne-cm) Myy Mxy Mxz Myz Mzz Mw Fit WVFMTGRD96 1.0 0.648E+22 0.973E+21 0.231E+22 0.103E+23 0.374E+22 -0.531E+22 4.0019 0.9982 WVFMTGRD96 2.0 0.977E+22 0.392E+22 0.246E+22 0.596E+22 0.217E+22 0.300E+20 3.9357 0.9802 WVFMTGRD96 3.0 0.114E+23 0.526E+22 0.257E+22 0.538E+22 0.196E+22 0.272E+22 3.9621 0.9477 WVFMTGRD96 4.0 0.128E+23 0.663E+22 0.267E+22 0.447E+22 0.193E+22 0.752E+22 4.0038 0.9166 WVFMTGRD96 5.0 0.133E+23 0.711E+22 0.248E+22 0.456E+22 0.189E+22 0.830E+22 4.0178 0.8874 WVFMTGRD96 6.0 0.140E+23 0.781E+22 0.247E+22 0.454E+22 0.188E+22 0.900E+22 4.0333 0.8606 WVFMTGRD96 7.0 0.143E+23 0.801E+22 0.229E+22 0.467E+22 0.184E+22 0.952E+22 4.0407 0.8391 WVFMTGRD96 8.0 0.148E+23 0.839E+22 0.255E+22 0.469E+22 0.194E+22 0.962E+22 4.0495 0.8170 WVFMTGRD96 9.0 0.148E+23 0.829E+22 0.237E+22 0.483E+22 0.190E+22 0.985E+22 4.0504 0.7982 WVFMTGRD96 10.0 0.150E+23 0.902E+22 0.238E+22 0.569E+22 0.201E+22 0.115E+23 4.0722 0.7784
The best solution is
WVFMTGRD96 1.0 0.648E+22 0.973E+21 0.231E+22 0.103E+23 0.374E+22 -0.531E+22 4.0019 0.9982
The complete moment tensor decomposition using the program mtinfo is given in the text file MTGRDinfo.txt. (Jost, M. L., and R. B. Herrmann (1989). A student's guide to and review of moment tensors, Seism. Res. Letters 60, 37-57. SRL_60_2_37-57.pdf.
The P-wave first motion mechanism corresponding to the best fit is
|
|
|
The best fit as a function of depth is given in the following figure:
|
|
|
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 component is plotted to the same scale and peak amplitudes are indicated by the numbers to the left of each trace. A pair of numbers is given in black at the right of each predicted traces. The upper number 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 lower number gives the percentage of variance reduction to characterize the individual goodness of fit (100% indicates a perfect fit).
The bandpass filter used in the processing and for the display was
cut o DIST/3.3 -20 o DIST/3.3 +50 rtr taper w 0.1 hp c 0.03 n 3 lp c 0.10 n 3
|
|
|
A check on the assumed source location is possible by looking at the time shifts between the observed and predicted traces. The time shifts for waveform matching arise for several reasons:
Time_shift = A + B cos Azimuth + C Sin Azimuth
The time shifts for this inversion lead to the next figure:
The derived shift in origin time and epicentral coordinates are given at the bottom of the figure.
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.
|
|
|
The program wvfmtgrd96 -DC 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:
cut o DIST/3.3 -20 o DIST/3.3 +50 rtr taper w 0.1 hp c 0.03 n 3 lp c 0.10 n 3The results of this grid search over depth are as follow:
MT Program H(km) Mxx(dyne-cm) Myy Mxy Mxz Myz Mzz Mw Fit WVFMTGRD96 1.0 0.600E+22 0.795E+21 0.218E+22 0.111E+23 0.402E+22 -0.679E+22 4.0221 0.9978 WVFMTGRD96 2.0 0.750E+22 0.994E+21 0.273E+22 0.670E+22 0.244E+22 -0.850E+22 3.9633 0.9242 WVFMTGRD96 3.0 0.692E+22 0.693E+21 0.222E+22 0.596E+22 0.241E+22 -0.761E+22 3.9325 0.7786 WVFMTGRD96 4.0 0.487E+22 0.483E+21 0.155E+22 -0.599E+22 -0.231E+22 -0.536E+22 3.8816 0.6726 WVFMTGRD96 5.0 0.453E+22 0.301E+21 0.125E+22 -0.545E+22 -0.222E+22 -0.483E+22 3.8549 0.6352 WVFMTGRD96 6.0 0.433E+22 0.145E+21 0.102E+22 -0.516E+22 -0.221E+22 -0.447E+22 3.8383 0.6140 WVFMTGRD96 7.0 0.313E+22 0.102E+21 0.722E+21 -0.543E+22 -0.215E+22 -0.323E+22 3.8169 0.6022 WVFMTGRD96 8.0 0.356E+22 -0.820E+21 -0.318E+21 -0.521E+22 -0.250E+22 -0.274E+22 3.8144 0.5956 WVFMTGRD96 9.0 0.216E+22 -0.625E+22 0.320E+22 -0.333E+22 -0.155E+22 0.409E+22 3.8440 0.6037 WVFMTGRD96 10.0 0.351E+22 -0.102E+22 -0.280E+21 -0.604E+22 -0.319E+22 -0.248E+22 3.8505 0.5902
The best solution is
WVFMTGRD96 1.0 0.600E+22 0.795E+21 0.218E+22 0.111E+23 0.402E+22 -0.679E+22 4.0221 0.9978
The complete moment tensor decomposition using the program mtinfo is given in the text file MTGRDDCinfo.txt. (Jost, M. L., and R. B. Herrmann (1989). A student's guide to and review of moment tensors, Seism. Res. Letters 60, 37-57. SRL_60_2_37-57.pdf.
The P-wave first motion mechanism corresponding to the best fit is
|
|
|
The best fit as a function of depth is given in the following figure:
|
|
|
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 component is plotted to the same scale and peak amplitudes are indicated by the numbers to the left of each trace. A pair of numbers is given in black at the right of each predicted traces. The upper number 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 lower number gives the percentage of variance reduction to characterize the individual goodness of fit (100% indicates a perfect fit).
The bandpass filter used in the processing and for the display was
cut o DIST/3.3 -20 o DIST/3.3 +50 rtr taper w 0.1 hp c 0.03 n 3 lp c 0.10 n 3
|
|
|
A check on the assumed source location is possible by looking at the time shifts between the observed and predicted traces. The time shifts for waveform matching arise for several reasons:
Time_shift = A + B cos Azimuth + C Sin Azimuth
The time shifts for this inversion lead to the next figure:
The derived shift in origin time and epicentral coordinates are given at the bottom of the figure.
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.
|
|
|
The program wvfmtgrd96 -DEV 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:
cut o DIST/3.3 -20 o DIST/3.3 +50 rtr taper w 0.1 hp c 0.03 n 3 lp c 0.10 n 3The results of this grid search over depth are as follow:
MT Program H(km) Mxx(dyne-cm) Myy Mxy Mxz Myz Mzz Mw Fit WVFMTGRD96 1.0 0.600E+22 0.795E+21 0.218E+22 0.111E+23 0.402E+22 -0.679E+22 4.0221 0.9978 WVFMTGRD96 2.0 0.749E+22 0.168E+22 0.244E+22 0.692E+22 0.252E+22 -0.918E+22 3.9733 0.9337 WVFMTGRD96 3.0 0.692E+22 0.693E+21 0.222E+22 0.596E+22 0.241E+22 -0.761E+22 3.9325 0.7786 WVFMTGRD96 4.0 0.535E+22 -0.153E+22 0.231E+22 -0.561E+22 -0.208E+22 -0.382E+22 3.8686 0.7034 WVFMTGRD96 5.0 0.415E+22 -0.243E+22 0.235E+22 -0.550E+22 -0.190E+22 -0.172E+22 3.8398 0.6824 WVFMTGRD96 6.0 0.375E+22 -0.262E+22 0.224E+22 -0.546E+22 -0.209E+22 -0.113E+22 3.8338 0.6781 WVFMTGRD96 7.0 0.317E+22 -0.356E+22 0.230E+22 -0.536E+22 -0.195E+22 0.391E+21 3.8310 0.6778 WVFMTGRD96 8.0 0.290E+22 -0.370E+22 0.252E+22 -0.536E+22 -0.196E+22 0.803E+21 3.8339 0.6790 WVFMTGRD96 9.0 0.269E+22 -0.421E+22 0.216E+22 -0.537E+22 -0.196E+22 0.152E+22 3.8359 0.6781 WVFMTGRD96 10.0 0.262E+22 -0.449E+22 0.248E+22 -0.606E+22 -0.234E+22 0.187E+22 3.8678 0.6741
The best solution is
WVFMTGRD96 1.0 0.600E+22 0.795E+21 0.218E+22 0.111E+23 0.402E+22 -0.679E+22 4.0221 0.9978
The complete moment tensor decomposition using the program mtinfo is given in the text file MTGRDDEVinfo.txt. (Jost, M. L., and R. B. Herrmann (1989). A student's guide to and review of moment tensors, Seism. Res. Letters 60, 37-57. SRL_60_2_37-57.pdf.
The P-wave first motion mechanism corresponding to the best fit is
|
|
|
The best fit as a function of depth is given in the following figure:
|
|
|
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 component is plotted to the same scale and peak amplitudes are indicated by the numbers to the left of each trace. A pair of numbers is given in black at the right of each predicted traces. The upper number 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 lower number gives the percentage of variance reduction to characterize the individual goodness of fit (100% indicates a perfect fit).
The bandpass filter used in the processing and for the display was
cut o DIST/3.3 -20 o DIST/3.3 +50 rtr taper w 0.1 hp c 0.03 n 3 lp c 0.10 n 3
|
|
|
A check on the assumed source location is possible by looking at the time shifts between the observed and predicted traces. The time shifts for waveform matching arise for several reasons:
Time_shift = A + B cos Azimuth + C Sin Azimuth
The time shifts for this inversion lead to the next figure:
The derived shift in origin time and epicentral coordinates are given at the bottom of the figure.
Thanks also to the many seismic network operators whose dedication make this effort possible: University of Nevada Reno, University of Alaska, University of Washington, Oregon State University, University of Utah, Montana Bureau of Mines, UC Berkely, Caltech, UC San Diego, Saint Louis University, University of Memphis, Lamont Doherty Earth Observatory, the Oklahoma Geological Survey, TexNet, the Iris stations, the Transportable Array of EarthScope and other networks.
The CUS model used for the waveform synthetic seismograms and for the surface wave eigenfunctions and dispersion is as follows:
MODEL.01 CUS Model with Q from simple gamma values 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 1.0000 5.0000 2.8900 2.5000 0.172E-02 0.387E-02 0.00 0.00 1.00 1.00 9.0000 6.1000 3.5200 2.7300 0.160E-02 0.363E-02 0.00 0.00 1.00 1.00 10.0000 6.4000 3.7000 2.8200 0.149E-02 0.336E-02 0.00 0.00 1.00 1.00 20.0000 6.7000 3.8700 2.9020 0.000E-04 0.000E-04 0.00 0.00 1.00 1.00 0.0000 8.1500 4.7000 3.3640 0.194E-02 0.431E-02 0.00 0.00 1.00 1.00