2004/10/20 06:59:18 52.90 9.60 0 4.5 Germany
USGS Felt map for this earthquake
USGS/SLU Moment Tensor Solution
ENS 2004/10/20 06:59:18:0 52.90 9.60 0.0 4.5 Germany
Stations used:
CH.BALST CH.SLE CH.SULZ CH.WILA CH.ZUR CZ.KHC CZ.NKC G.ECH
GE.IBBN GE.WLF GR.BRG GR.BSEG GR.BUG GR.CLL GR.CLZ GR.FUR
GR.GEC2 GR.MOX GR.NRDL GR.UBBA GR.WET II.BFO IU.GRFO NL.HGN
NL.WTSB OE.MOA OE.WTTA SX.TANN
Filtering commands used:
cut a -30 a 210
rtr
taper w 0.1
hp c 0.02 n 3
lp c 0.05 n 3
Best Fitting Double Couple
Mo = 3.31e+22 dyne-cm
Mw = 4.28
Z = 15 km
Plane Strike Dip Rake
NP1 130 70 -25
NP2 229 67 -158
Principal Axes:
Axis Value Plunge Azimuth
T 3.31e+22 2 180
N 0.00e+00 58 274
P -3.31e+22 32 89
Moment Tensor: (dyne-cm)
Component Value
Mxx 3.31e+22
Mxy -4.68e+20
Mxz -1.61e+21
Myy -2.41e+22
Myz -1.48e+22
Mzz -9.00e+21
##############
######################
############################
##############################
-########################---------
---###################--------------
-----###############------------------
-------############---------------------
---------#######------------------------
-----------####------------------- -----
---------------------------------- P -----
------------##-------------------- -----
----------######--------------------------
--------##########----------------------
-------#############--------------------
-----#################----------------
---#####################------------
--#########################-------
##############################
############################
######### ##########
##### T ######
Global CMT Convention Moment Tensor:
R T P
-9.00e+21 -1.61e+21 1.48e+22
-1.61e+21 3.31e+22 4.68e+20
1.48e+22 4.68e+20 -2.41e+22
Details of the solution is found at
http://www.eas.slu.edu/eqc/eqc_mt/MECH.EU/20041020065918/index.html
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STK = 130
DIP = 70
RAKE = -25
MW = 4.28
HS = 15.0
The NDK file is 20041020065918.ndk The waveform inversion is preferred.
The following compares this source inversion to others
USGS/SLU Moment Tensor Solution
ENS 2004/10/20 06:59:18:0 52.90 9.60 0.0 4.5 Germany
Stations used:
CH.BALST CH.SLE CH.SULZ CH.WILA CH.ZUR CZ.KHC CZ.NKC G.ECH
GE.IBBN GE.WLF GR.BRG GR.BSEG GR.BUG GR.CLL GR.CLZ GR.FUR
GR.GEC2 GR.MOX GR.NRDL GR.UBBA GR.WET II.BFO IU.GRFO NL.HGN
NL.WTSB OE.MOA OE.WTTA SX.TANN
Filtering commands used:
cut a -30 a 210
rtr
taper w 0.1
hp c 0.02 n 3
lp c 0.05 n 3
Best Fitting Double Couple
Mo = 3.31e+22 dyne-cm
Mw = 4.28
Z = 15 km
Plane Strike Dip Rake
NP1 130 70 -25
NP2 229 67 -158
Principal Axes:
Axis Value Plunge Azimuth
T 3.31e+22 2 180
N 0.00e+00 58 274
P -3.31e+22 32 89
Moment Tensor: (dyne-cm)
Component Value
Mxx 3.31e+22
Mxy -4.68e+20
Mxz -1.61e+21
Myy -2.41e+22
Myz -1.48e+22
Mzz -9.00e+21
##############
######################
############################
##############################
-########################---------
---###################--------------
-----###############------------------
-------############---------------------
---------#######------------------------
-----------####------------------- -----
---------------------------------- P -----
------------##-------------------- -----
----------######--------------------------
--------##########----------------------
-------#############--------------------
-----#################----------------
---#####################------------
--#########################-------
##############################
############################
######### ##########
##### T ######
Global CMT Convention Moment Tensor:
R T P
-9.00e+21 -1.61e+21 1.48e+22
-1.61e+21 3.31e+22 4.68e+20
1.48e+22 4.68e+20 -2.41e+22
Details of the solution is found at
http://www.eas.slu.edu/eqc/eqc_mt/MECH.EU/20041020065918/index.html
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Cesca et al 2010 JGR Vol 115 B06304 do1:10.1029/JB006450
ENS 2004/10/20 06:59:18:0 53.01 9.63 6.3 4.5 Rotenburg, Germany
Best Fitting Double Couple
Mo = 5.01e+22 dyne-cm
Mw = 4.40
Z = 6 km
Plane Strike Dip Rake
NP1 328 67 -126
NP2 210 42 -36
Principal Axes:
Axis Value Plunge Azimuth
T 5.01e+22 14 84
N 0.00e+00 33 344
P -5.01e+22 53 194
Moment Tensor: (dyne-cm)
Component Value
Mxx -1.62e+22
Mxy 8.79e+20
Mxz 2.46e+22
Myy 4.55e+22
Myz 1.77e+22
Mzz -2.93e+22
--------------
---------------#######
#######-------##############
###########-##################
###########----###################
###########-------##################
##########----------##################
##########-------------#################
#########---------------############ #
#########-----------------########### T ##
########-------------------########## ##
########--------------------##############
#######----------------------#############
######-----------------------###########
######---------- -----------##########
#####---------- P -----------#########
####---------- ------------#######
####------------------------######
##------------------------####
##-----------------------###
----------------------
--------------
Global CMT Convention Moment Tensor:
R T P
-2.93e+22 2.46e+22 -1.77e+22
2.46e+22 -1.62e+22 -8.79e+20
-1.77e+22 -8.79e+20 4.55e+22
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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 a -30 a 210 rtr taper w 0.1 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 1.0 140 65 20 3.95 0.1964
WVFGRD96 2.0 145 55 30 4.08 0.2551
WVFGRD96 3.0 140 65 30 4.10 0.2905
WVFGRD96 4.0 140 65 35 4.14 0.3142
WVFGRD96 5.0 140 65 30 4.15 0.3374
WVFGRD96 6.0 140 65 30 4.17 0.3470
WVFGRD96 7.0 140 70 30 4.18 0.3580
WVFGRD96 8.0 140 70 30 4.21 0.3711
WVFGRD96 9.0 140 70 30 4.22 0.3742
WVFGRD96 10.0 130 70 -30 4.23 0.3737
WVFGRD96 11.0 130 70 -30 4.24 0.3874
WVFGRD96 12.0 130 70 -30 4.25 0.3943
WVFGRD96 13.0 130 70 -25 4.26 0.3987
WVFGRD96 14.0 130 70 -25 4.27 0.4032
WVFGRD96 15.0 130 70 -25 4.28 0.4032
WVFGRD96 16.0 135 75 -20 4.28 0.4031
WVFGRD96 17.0 135 75 -20 4.28 0.4010
WVFGRD96 18.0 135 75 -20 4.29 0.3974
WVFGRD96 19.0 135 75 -20 4.30 0.3928
WVFGRD96 20.0 135 75 -20 4.30 0.3869
WVFGRD96 21.0 135 75 -20 4.31 0.3806
WVFGRD96 22.0 135 75 -15 4.31 0.3736
WVFGRD96 23.0 135 75 -15 4.32 0.3662
WVFGRD96 24.0 135 80 -15 4.32 0.3586
WVFGRD96 25.0 135 80 -15 4.33 0.3504
WVFGRD96 26.0 135 80 -15 4.33 0.3419
WVFGRD96 27.0 135 80 -10 4.34 0.3333
WVFGRD96 28.0 135 80 -10 4.35 0.3278
WVFGRD96 29.0 135 80 -10 4.35 0.3193
The best solution is
WVFGRD96 15.0 130 70 -25 4.28 0.4032
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 a -30 a 210 rtr taper w 0.1 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. |
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.
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 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=Thu Jul 3 03:25:58 CDT 2014