2010/06/16 22:39:41 38.832 16.146 8.6 3.7 Italy
USGS Felt map for this earthquake
USGS/SLU Moment Tensor Solution
ENS 2010/06/16 22:39:41:0 38.83 16.15 8.6 3.7 Italy
Stations used:
IV.LADO IV.MMME IV.MMN IV.MNOV IV.MPAZ IV.MSCL IV.MSRU
IV.MTTG IV.PIPA IV.PLAC MN.CEL
Filtering commands used:
hp c 0.02 n 3
lp c 0.10 n 3
Best Fitting Double Couple
Mo = 6.76e+21 dyne-cm
Mw = 3.82
Z = 10 km
Plane Strike Dip Rake
NP1 211 82 -145
NP2 115 55 -10
Principal Axes:
Axis Value Plunge Azimuth
T 6.76e+21 18 338
N 0.00e+00 54 222
P -6.76e+21 30 79
Moment Tensor: (dyne-cm)
Component Value
Mxx 5.08e+21
Mxy -3.08e+21
Mxz 1.25e+21
Myy -3.98e+21
Myz -3.63e+21
Mzz -1.10e+21
##############
### ###############-
###### T ##############-----
####### ############--------
#######################-----------
######################--------------
######################----------------
--####################------------------
---#################------------- ----
-----###############-------------- P -----
------#############--------------- -----
-------###########------------------------
---------########-------------------------
-----------####-------------------------
-------------#--------------------------
------------####----------------------
----------##########--------------##
--------##########################
------########################
----########################
######################
##############
Global CMT Convention Moment Tensor:
R T P
-1.10e+21 1.25e+21 3.63e+21
1.25e+21 5.08e+21 3.08e+21
3.63e+21 3.08e+21 -3.98e+21
Details of the solution is found at
http://www.eas.slu.edu/eqc/eqc_mt/MECH.IT/20100616223941/index.html
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STK = 115
DIP = 55
RAKE = -10
MW = 3.82
HS = 10.0
The waveform inversion is preferred.
The following compares this source inversion to others
USGS/SLU Moment Tensor Solution
ENS 2010/06/16 22:39:41:0 38.83 16.15 8.6 3.7 Italy
Stations used:
IV.LADO IV.MMME IV.MMN IV.MNOV IV.MPAZ IV.MSCL IV.MSRU
IV.MTTG IV.PIPA IV.PLAC MN.CEL
Filtering commands used:
hp c 0.02 n 3
lp c 0.10 n 3
Best Fitting Double Couple
Mo = 6.76e+21 dyne-cm
Mw = 3.82
Z = 10 km
Plane Strike Dip Rake
NP1 211 82 -145
NP2 115 55 -10
Principal Axes:
Axis Value Plunge Azimuth
T 6.76e+21 18 338
N 0.00e+00 54 222
P -6.76e+21 30 79
Moment Tensor: (dyne-cm)
Component Value
Mxx 5.08e+21
Mxy -3.08e+21
Mxz 1.25e+21
Myy -3.98e+21
Myz -3.63e+21
Mzz -1.10e+21
##############
### ###############-
###### T ##############-----
####### ############--------
#######################-----------
######################--------------
######################----------------
--####################------------------
---#################------------- ----
-----###############-------------- P -----
------#############--------------- -----
-------###########------------------------
---------########-------------------------
-----------####-------------------------
-------------#--------------------------
------------####----------------------
----------##########--------------##
--------##########################
------########################
----########################
######################
##############
Global CMT Convention Moment Tensor:
R T P
-1.10e+21 1.25e+21 3.63e+21
1.25e+21 5.08e+21 3.08e+21
3.63e+21 3.08e+21 -3.98e+21
Details of the solution is found at
http://www.eas.slu.edu/eqc/eqc_mt/MECH.IT/20100616223941/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 1.0 295 70 -15 3.49 0.4023
WVFGRD96 2.0 295 70 -15 3.55 0.4377
WVFGRD96 3.0 300 75 20 3.59 0.4644
WVFGRD96 4.0 120 65 15 3.64 0.4984
WVFGRD96 5.0 110 35 -20 3.79 0.5379
WVFGRD96 6.0 110 40 -20 3.80 0.5684
WVFGRD96 7.0 110 45 -20 3.81 0.5871
WVFGRD96 8.0 115 50 -10 3.80 0.5965
WVFGRD96 9.0 115 55 -10 3.80 0.6019
WVFGRD96 10.0 115 55 -10 3.82 0.6030
WVFGRD96 11.0 115 55 -10 3.84 0.6009
WVFGRD96 12.0 115 60 -10 3.84 0.5967
WVFGRD96 13.0 115 60 -10 3.85 0.5895
WVFGRD96 14.0 115 60 -10 3.87 0.5793
WVFGRD96 15.0 115 55 -10 3.89 0.5671
WVFGRD96 16.0 120 55 10 3.90 0.5555
WVFGRD96 17.0 120 60 15 3.90 0.5421
WVFGRD96 18.0 120 60 15 3.90 0.5285
WVFGRD96 19.0 120 65 15 3.90 0.5162
WVFGRD96 20.0 120 70 15 3.90 0.5027
WVFGRD96 21.0 120 70 15 3.91 0.4905
WVFGRD96 22.0 295 55 -15 3.92 0.4844
WVFGRD96 23.0 295 55 -15 3.93 0.4782
WVFGRD96 24.0 295 55 -15 3.94 0.4718
WVFGRD96 25.0 295 55 -15 3.95 0.4643
WVFGRD96 26.0 295 55 -15 3.96 0.4589
WVFGRD96 27.0 295 60 -15 3.96 0.4544
WVFGRD96 28.0 295 60 -15 3.97 0.4511
WVFGRD96 29.0 295 60 -15 3.99 0.4499
The best solution is
WVFGRD96 10.0 115 55 -10 3.82 0.6030
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=Thu Jun 17 04:08:25 CDT 2010