Location

2013/06/30 14:40:08 44.171 10.205 9.8 4.4 Italy

Arrival Times (from USGS)

Arrival time list

Felt Map

USGS Felt map for this earthquake

USGS Felt reports page for

Focal Mechanism

 SLU Moment Tensor Solution
 ENS  2013/06/30 14:40:08:0  44.17   10.20   9.8 4.4 Italy 
 
 Stations used:
   CH.FUSIO CH.VDL FR.CALF FR.EILF FR.ISO FR.SAOF FR.SMPL 
   GU.ENR GU.FINB GU.GORR GU.MAIM GU.NEGI GU.PCP GU.POPM 
   IV.AOI IV.ARCI IV.ARVD IV.ASQU IV.BDI IV.BOB IV.CAFI 
   IV.CESI IV.CESX IV.CING IV.CRE IV.CRMI IV.CSNT IV.DOI 
   IV.FDMO IV.FSSB IV.GROG IV.LNSS IV.MAON IV.MSSA IV.PARC 
   IV.PESA IV.QLNO IV.ROVR IV.SACS IV.TEOL IV.TOLF IV.ZCCA 
   MN.TUE MN.VLC 
 
 Filtering commands used:
   cut a -30 a 120
   rtr
   taper w 0.1
   hp c 0.02 n 3
   lp c 0.05 n 3
 
 Best Fitting Double Couple
  Mo = 5.96e+22 dyne-cm
  Mw = 4.45 
  Z  = 3 km
  Plane   Strike  Dip  Rake
   NP1      251    52   -117
   NP2      110    45   -60
  Principal Axes:
   Axis    Value   Plunge  Azimuth
    T   5.96e+22      4     359
    N   0.00e+00     21     268
    P  -5.96e+22     69      99

 Moment Tensor: (dyne-cm)
    Component   Value
       Mxx     5.91e+22
       Mxy     4.47e+20
       Mxz     7.20e+21
       Myy    -7.50e+21
       Myz    -1.98e+22
       Mzz    -5.16e+22
                                                     
                                                     
                                                     
                                                     
                     ##### T ######                  
                 #########   ##########              
              ############################           
             ##############################          
           ##################################        
          ###################-----------######       
         ##############----------------------##      
        -##########-----------------------------     
        -########-------------------------------     
       ---####-----------------------------------    
       ---###-------------------   --------------    
       ------------------------- P --------------    
       ---###-------------------   --------------    
        -######---------------------------------     
        #########-------------------------------     
         ##########---------------------------#      
          #############--------------------###       
           ###################-------########        
             ##############################          
              ############################           
                 ######################              
                     ##############                  
                                                     
                                                     
                                                     
 Global CMT Convention Moment Tensor:
      R          T          P
 -5.16e+22   7.20e+21   1.98e+22 
  7.20e+21   5.91e+22  -4.47e+20 
  1.98e+22  -4.47e+20  -7.50e+21 


Details of the solution is found at

http://www.eas.slu.edu/eqc/eqc_mt/MECH.IT/20130630144008/index.html
        

Preferred Solution

The preferred solution from an analysis of the surface-wave spectral amplitude radiation pattern, waveform inversion and first motion observations is

      STK = 110
      DIP = 45
     RAKE = -60
       MW = 4.45
       HS = 3.0

The waveform inversion is preferred.

Moment Tensor Comparison

The following compares this source inversion to others
SLU
INGVTDMT
 SLU Moment Tensor Solution
 ENS  2013/06/30 14:40:08:0  44.17   10.20   9.8 4.4 Italy 
 
 Stations used:
   CH.FUSIO CH.VDL FR.CALF FR.EILF FR.ISO FR.SAOF FR.SMPL 
   GU.ENR GU.FINB GU.GORR GU.MAIM GU.NEGI GU.PCP GU.POPM 
   IV.AOI IV.ARCI IV.ARVD IV.ASQU IV.BDI IV.BOB IV.CAFI 
   IV.CESI IV.CESX IV.CING IV.CRE IV.CRMI IV.CSNT IV.DOI 
   IV.FDMO IV.FSSB IV.GROG IV.LNSS IV.MAON IV.MSSA IV.PARC 
   IV.PESA IV.QLNO IV.ROVR IV.SACS IV.TEOL IV.TOLF IV.ZCCA 
   MN.TUE MN.VLC 
 
 Filtering commands used:
   cut a -30 a 120
   rtr
   taper w 0.1
   hp c 0.02 n 3
   lp c 0.05 n 3
 
 Best Fitting Double Couple
  Mo = 5.96e+22 dyne-cm
  Mw = 4.45 
  Z  = 3 km
  Plane   Strike  Dip  Rake
   NP1      251    52   -117
   NP2      110    45   -60
  Principal Axes:
   Axis    Value   Plunge  Azimuth
    T   5.96e+22      4     359
    N   0.00e+00     21     268
    P  -5.96e+22     69      99

 Moment Tensor: (dyne-cm)
    Component   Value
       Mxx     5.91e+22
       Mxy     4.47e+20
       Mxz     7.20e+21
       Myy    -7.50e+21
       Myz    -1.98e+22
       Mzz    -5.16e+22
                                                     
                                                     
                                                     
                                                     
                     ##### T ######                  
                 #########   ##########              
              ############################           
             ##############################          
           ##################################        
          ###################-----------######       
         ##############----------------------##      
        -##########-----------------------------     
        -########-------------------------------     
       ---####-----------------------------------    
       ---###-------------------   --------------    
       ------------------------- P --------------    
       ---###-------------------   --------------    
        -######---------------------------------     
        #########-------------------------------     
         ##########---------------------------#      
          #############--------------------###       
           ###################-------########        
             ##############################          
              ############################           
                 ######################              
                     ##############                  
                                                     
                                                     
                                                     
 Global CMT Convention Moment Tensor:
      R          T          P
 -5.16e+22   7.20e+21   1.98e+22 
  7.20e+21   5.91e+22  -4.47e+20 
  1.98e+22  -4.47e+20  -7.50e+21 


Details of the solution is found at

http://www.eas.slu.edu/eqc/eqc_mt/MECH.IT/20130630144008/index.html
	

Waveform Inversion

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.
Location of broadband stations used for waveform inversion

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 120
rtr
taper w 0.1
hp c 0.02 n 3
lp c 0.05 n 3
The results of this grid search from 0.5 to 19 km depth are as follow:

           DEPTH  STK   DIP  RAKE   MW    FIT
WVFGRD96    1.0   115    45   -50   4.36 0.5507
WVFGRD96    2.0   115    40   -50   4.42 0.5933
WVFGRD96    3.0   110    45   -60   4.45 0.6090
WVFGRD96    4.0   100    40   -75   4.48 0.5859
WVFGRD96    5.0   105    40   -70   4.52 0.5937
WVFGRD96    6.0   105    40   -65   4.49 0.5261
WVFGRD96    7.0   120    50   -40   4.42 0.4655
WVFGRD96    8.0   130    55    -5   4.34 0.4384
WVFGRD96    9.0   130    60     5   4.34 0.4449
WVFGRD96   10.0   135    60    10   4.36 0.4523
WVFGRD96   11.0   135    60    15   4.37 0.4600
WVFGRD96   12.0   135    60    15   4.38 0.4649
WVFGRD96   13.0   135    65    15   4.39 0.4698
WVFGRD96   14.0   135    65    20   4.40 0.4737
WVFGRD96   15.0   135    65    15   4.41 0.4693
WVFGRD96   16.0   135    65    15   4.42 0.4691
WVFGRD96   17.0   135    65    15   4.43 0.4674
WVFGRD96   18.0   135    65    15   4.43 0.4650
WVFGRD96   19.0   135    65    20   4.44 0.4621
WVFGRD96   20.0   135    65    15   4.44 0.4590
WVFGRD96   21.0   135    65    20   4.45 0.4557
WVFGRD96   22.0   135    65    20   4.46 0.4524
WVFGRD96   23.0   135    70    20   4.47 0.4495
WVFGRD96   24.0   135    70    20   4.48 0.4474
WVFGRD96   25.0   135    70    20   4.49 0.4451
WVFGRD96   26.0   135    70    20   4.50 0.4433
WVFGRD96   27.0   135    70    20   4.51 0.4418
WVFGRD96   28.0   135    70    20   4.52 0.4416
WVFGRD96   29.0   135    70    20   4.54 0.4416

The best solution is

WVFGRD96    3.0   110    45   -60   4.45 0.6090

The mechanism correspond to the best fit is
Figure 1. Waveform inversion focal mechanism

The best fit as a function of depth is given in the following figure:

Figure 2. Depth sensitivity for waveform mechanism

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 120
rtr
taper w 0.1
hp c 0.02 n 3
lp c 0.05 n 3
Figure 3. Waveform comparison for selected depth
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:

Assuming only a mislocation, the time shifts are fit to a functional form:

 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.

Discussion

Velocity Model

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    

Quality Control

Here we tabulate the reasons for not using certain digital data sets

The following stations did not have a valid response files:

DATE=Sun Jun 30 14:16:46 CDT 2013

Last Changed 2013/06/30