2010/09/03 02:24:25 42.516 13.223 10.0 3.3 Italy
USGS Felt map for this earthquake
USGS/SLU Moment Tensor Solution
ENS 2010/09/03 02:24:25:0 42.52 13.22 10.0 3.3 Italy
Stations used:
IV.ARVD IV.CAMP IV.CING IV.CRE IV.FAGN IV.FDMO IV.FIAM
IV.GUMA IV.LATE IV.MIDA IV.MNS IV.MODR IV.MTCE IV.MURB
IV.PIEI IV.POFI IV.RNI2 IV.SGG IV.SNTG IV.T0104 IV.TERO
IV.TOLF MN.AQU
Filtering commands used:
hp c 0.02 n 3
lp c 0.10 n 3
Best Fitting Double Couple
Mo = 1.08e+21 dyne-cm
Mw = 3.29
Z = 5 km
Plane Strike Dip Rake
NP1 75 60 -125
NP2 310 45 -45
Principal Axes:
Axis Value Plunge Azimuth
T 1.08e+21 8 190
N 0.00e+00 30 95
P -1.08e+21 59 294
Moment Tensor: (dyne-cm)
Component Value
Mxx 9.84e+20
Mxy 2.83e+20
Mxz -3.48e+20
Myy -2.17e+20
Myz 4.15e+20
Mzz -7.66e+20
##############
######################
############################
-------------#################
-------------------###############
-----------------------#############
---------------------------###########
-----------------------------###########
----------- -----------------#########
------------ P ------------------#######--
------------ --------------------###----
------------------------------------------
---------------------------------###------
-----------------------------#######----
##-----------------------###########----
#######---------###################---
##################################--
#################################-
##############################
############################
###### #############
## T #########
Global CMT Convention Moment Tensor:
R T P
-7.66e+20 -3.48e+20 -4.15e+20
-3.48e+20 9.84e+20 -2.83e+20
-4.15e+20 -2.83e+20 -2.17e+20
Details of the solution is found at
http://www.eas.slu.edu/eqc/eqc_mt/MECH.IT/20100903022425/index.html
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STK = 310
DIP = 45
RAKE = -45
MW = 3.29
HS = 5.0
The waveform inversion is preferred.
The following compares this source inversion to others
USGS/SLU Moment Tensor Solution
ENS 2010/09/03 02:24:25:0 42.52 13.22 10.0 3.3 Italy
Stations used:
IV.ARVD IV.CAMP IV.CING IV.CRE IV.FAGN IV.FDMO IV.FIAM
IV.GUMA IV.LATE IV.MIDA IV.MNS IV.MODR IV.MTCE IV.MURB
IV.PIEI IV.POFI IV.RNI2 IV.SGG IV.SNTG IV.T0104 IV.TERO
IV.TOLF MN.AQU
Filtering commands used:
hp c 0.02 n 3
lp c 0.10 n 3
Best Fitting Double Couple
Mo = 1.08e+21 dyne-cm
Mw = 3.29
Z = 5 km
Plane Strike Dip Rake
NP1 75 60 -125
NP2 310 45 -45
Principal Axes:
Axis Value Plunge Azimuth
T 1.08e+21 8 190
N 0.00e+00 30 95
P -1.08e+21 59 294
Moment Tensor: (dyne-cm)
Component Value
Mxx 9.84e+20
Mxy 2.83e+20
Mxz -3.48e+20
Myy -2.17e+20
Myz 4.15e+20
Mzz -7.66e+20
##############
######################
############################
-------------#################
-------------------###############
-----------------------#############
---------------------------###########
-----------------------------###########
----------- -----------------#########
------------ P ------------------#######--
------------ --------------------###----
------------------------------------------
---------------------------------###------
-----------------------------#######----
##-----------------------###########----
#######---------###################---
##################################--
#################################-
##############################
############################
###### #############
## T #########
Global CMT Convention Moment Tensor:
R T P
-7.66e+20 -3.48e+20 -4.15e+20
-3.48e+20 9.84e+20 -2.83e+20
-4.15e+20 -2.83e+20 -2.17e+20
Details of the solution is found at
http://www.eas.slu.edu/eqc/eqc_mt/MECH.IT/20100903022425/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 0.02 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 1.0 315 35 -20 3.12 0.4125
WVFGRD96 2.0 315 35 -25 3.18 0.4778
WVFGRD96 3.0 315 40 -35 3.20 0.5425
WVFGRD96 4.0 310 45 -50 3.24 0.5804
WVFGRD96 5.0 310 45 -45 3.29 0.5911
WVFGRD96 6.0 310 45 -50 3.30 0.5782
WVFGRD96 7.0 320 50 -35 3.27 0.5516
WVFGRD96 8.0 330 60 -15 3.24 0.5235
WVFGRD96 9.0 330 65 -5 3.25 0.5060
WVFGRD96 10.0 330 65 5 3.27 0.4921
WVFGRD96 11.0 330 65 0 3.27 0.4754
WVFGRD96 12.0 330 65 0 3.28 0.4575
WVFGRD96 13.0 325 65 -5 3.29 0.4392
WVFGRD96 14.0 325 65 -5 3.30 0.4218
WVFGRD96 15.0 325 65 -5 3.32 0.4056
WVFGRD96 16.0 325 65 -10 3.32 0.3907
WVFGRD96 17.0 325 65 -10 3.33 0.3782
WVFGRD96 18.0 325 70 -15 3.34 0.3666
WVFGRD96 19.0 325 70 -20 3.34 0.3569
WVFGRD96 20.0 325 70 -20 3.35 0.3479
WVFGRD96 21.0 325 70 -20 3.36 0.3401
WVFGRD96 22.0 325 65 -15 3.37 0.3350
WVFGRD96 23.0 325 65 -20 3.38 0.3323
WVFGRD96 24.0 325 65 -20 3.39 0.3301
WVFGRD96 25.0 325 65 -20 3.40 0.3303
WVFGRD96 26.0 325 65 -20 3.41 0.3316
WVFGRD96 27.0 320 65 -20 3.43 0.3337
WVFGRD96 28.0 320 65 -20 3.45 0.3358
WVFGRD96 29.0 320 65 -20 3.47 0.3397
The best solution is
WVFGRD96 5.0 310 45 -45 3.29 0.5911
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. 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 0.10 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. |
The nnCIA used for the waveform synthetic seismograms and for the surface wave eigenfunctions and dispersion is as follows:
MODEL.01
C.It. A. Di Luzio et al Earth Plan Lettrs 280 (2009) 1-12 Fig 5. 7-8 MODEL/SURF3
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
1.5000 3.7497 2.1436 2.2753 0.500E-02 0.100E-01 0.00 0.00 1.00 1.00
3.0000 4.9399 2.8210 2.4858 0.500E-02 0.100E-01 0.00 0.00 1.00 1.00
3.0000 6.0129 3.4336 2.7058 0.500E-02 0.100E-01 0.00 0.00 1.00 1.00
7.0000 5.5516 3.1475 2.6093 0.167E-02 0.333E-02 0.00 0.00 1.00 1.00
15.0000 5.8805 3.3583 2.6770 0.167E-02 0.333E-02 0.00 0.00 1.00 1.00
6.0000 7.1059 4.0081 3.0002 0.167E-02 0.333E-02 0.00 0.00 1.00 1.00
8.0000 7.1000 3.9864 3.0120 0.167E-02 0.333E-02 0.00 0.00 1.00 1.00
0.0000 7.9000 4.4036 3.2760 0.167E-02 0.333E-02 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=Fri Sep 3 06:41:20 CDT 2010