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Moment Tensor Catalog Format Description


Each event in the online catalog contains a minimum of 3 lines. For example,

event       0  mm/dd/yyyy hr:mn:sec latitude longitude dep mag location
            1  st1 err dp1 err rk1 err st2 err dp2 err rk2 err hh  dur  mom ex  mw
           -1 frequency  stations *
            2  st1 err dp1 err rk1 err st2 err dp2 err rk2 err hh  dur  mom ex  mw
           -2 frequency  stations *
idah88196   0  07/14/1988 17:31:33.1  44.456 -114.083   5.0 4.9 Idaho
            1 115      48      -94     301      42     -86      6. -0.5 9.30e22 4.6
           -1 0.02 0.06  ANMO PAS SAO CMB MHC BKS LON 
utah89030   0  01/30/1989 04:06:22.7  38.820 -111.610  24.0 5.0 Utah
            1 205      87        4     115      86     177     18. -0.5 8.40e23 5.2
           -1 0.02 0.06  HRV SCP IPAS SAO MHC CMB BKS COL 
mono90297   0  10/24/1990 06:15:20.7  38.047 -119.157  12.0 5.4 MonoLake
            1 144      80      184      53      86     -10      0   0.0 8.50e23 5.3
           -1 0.02 0.06  ARC BKS CMB MHC SAO STAN
            2 322      83      162      54      72       7      0   0.0 9.00e23 5.3
           -2 0.00 0.00  GSC PAS

The first line describes the event, with an event descriptor, a line id, the origin time, the location (latitude, longitude, depth in km), the magnitude, and the location code. The line id of 0 indicates that it is an event line.

idah88196 0 07/14/1988 17:31:33.1 44.456 -114.083 5.0 4.9 Idaho

Then there will be a series of two-line entries, one for each moment tensor solution. The line id in each indicates the type of the moment tensor solution (1 and -1 indicate the surface-wave frequency-domain solutions, 2 and -2 indicate the complete-waveform time-domain solutions, and 3 and -3 indicate a near-field waveform inversion.

The first of the two moment tensor lines indicates the strike (st1, st2), rake (rk1, rk2), and dip (dp1 , dp2) of the two possible nodal planes, the centroid depth (in km), the source half-duration (in seconds), scalar seismic moment, and Mw;

1 st1 err dp1 err rk1 err st2 err dp2 err rk2 err hh dur mom ex mw 1 115 48 -94 301 42 -86 6. -0.5 9.30e22 4.6

The second of the two moment tensor lines provides information about the stations used in the inversion and the frequncy range:

-1 0.02 0.06 ANMO PAS SAO CMB MHC BKS LON