31. Wadati

This is a program to make Wadati diagrams and apparent velocity from a Nordic file with one or many events. The apparent velocity is calculated from the arrival times and the calculated epicentral distances as given in the S-file. The apparent velocity is thus approximate and affected by the location.
The purpose of the program is to calculate Vp/Vs values for individual events and calculate the average for a group of events. In addition, the program can calculate the apparent velocity for each event based on P or S-times. Wadati diagrams with plot can also be calculated directly from EEV.

The information can be used to obtain a first impression of crustal parameters. For each calculation, events can be selected based on: Minimum number of stations, maximum rms of the fit (S-P vs P, or arrival times), and minimum correlation coefficient of the fit. For the apparent velocity calculation, the data can also be selected in distance and azimuth ranges.

The output gives:

T0 :	Wadati calculated origin time
N :	Number of stations used for Vp/Vs
VPS :	Vp/Vs ratio
NP :	Number of stations for P- velocity
NS :	Number of stations for S-velocity
AVSP:	Average S-P times with sd
AVDI:	Average distance with sd

The average Vp/Vs is calculated for the whole data set. Individual Vp/Vs values outside the range 1.53 to 1.93 are excluded. An output file wadati.out is generated. A minimum of 3 stations is required for an event to be used. Only same type phases are used (like PG and SG).

Example of a run to calculate Vp/Vs

Input file name
collect.out
 Wadati (1), apparent velocity (2) or both (3) ?
1
 Wadati parameters:  Minimum number of stations
3
 Maximum rms
1
 Minimum correlation coefficient
0.9
 1994  616 1841 28.3 No data for Wadati
 1994 10 4 1322 55.8 No data for Wadati
 1995  822 0141  5.3 T0:  141   8.1 N:    8 VPS:  1.84 RMS:   1.19 CORR:  0.997
 1995 1120 0401 58.9 T0:  4 1  59.5 N:    7 VPS:  1.76 RMS:   0.87 CORR:  0.995
 1996  6 3 1955 35.6 No data for Wadati
 1996  6 3 1955 35.6 No data for Wadati
 1996  6 3 1955 40.1 No data for Wadati
 1996  6 6 0648 29.8 T0:  648   1.1 N:   22 VPS:  1.51 RMS:  11.00 CORR:  0.380
 1996  6 6 0648 30.6 T0:  648  38.7 N:    3 VPS:  2.16 RMS:   0.80 CORR:  1.000
 1996  6 6 0648 29.8 No data for Wadati
 1996  6 7 1325 28.5 T0: 1325  28.1 N:    9 VPS:  1.72 RMS:   1.06 CORR:  0.973
 1996  6 7 1325 29.1 T0: 1325  28.1 N:    9 VPS:  1.72 RMS:   1.06 CORR:  0.973
 1996  610  1 4 47.0 No data for Wadati
 1996  610  1 4 47.0 No data for Wadati
 1996  623 0117 57.8 No data for Wadati
 1996  623 0117 58.1 No data for Wadati
 1996  625 0337 31.7 T0:  337  33.1 N:   21 VPS:  1.75 RMS:   1.36 CORR:  0.999
 1996  7 5 0220 46.5 T0:  220  45.8 N:    6 VPS:  1.76 RMS:   0.28 CORR:  0.999
 1996  713 0556 46.0 No data for Wadati
 1996  718 0946 51.4 No data for Wadati
 1996  718 2255  6.0 No data for Wadati
 1996  726 0742 12.0 T0:  742  11.8 N:    6 VPS:  1.74 RMS:   0.47 CORR:  0.993

 Number of events for which vp/vs were calculated            9
 Number of events selected for average                       3


 Average VP/VS =  1.75  SD=  0.01 N=    3

Example of a run to calculate apparent velocity

Input file name
collect.out
 Wadati (1), apparent velocity (2) or both (3) ?
2
 Apparent velocity parameters:  Distance range
50 200  Azimuth range
0 180
 Minimum number of stations
2
 Maximum rms
1
AVSP:  30.212.7  AVDI: 152.0  30.7 NP:    4 VP :  6.95 RMS:   0.20 CORR:  1.000
                 AVDI: 143.3  31.1 NS:    3 VS :  3.82 RMS:   0.25 CORR:  1.000
AVSP:  23.0 9.5  AVDI: 158.7  26.6 NP:    3 VP :  6.76 RMS:   0.00 CORR:  1.000
                 AVDI:  90.5  35.8 NS:    6 VS :  3.72 RMS:   1.79 CORR:  0.998
                 AVDI:  89.0  35.6 NS:    6 VS :  3.69 RMS:   2.78 CORR:  0.996
AVSP:  50.536.0  AVDI: 145.8  40.8 NP:    6 VP :  7.60 RMS:   0.42 CORR:  1.000
                 AVDI: 116.3  38.2 NS:    3 VS :  3.97 RMS:   0.04 CORR:  1.000
                 AVDI: 118.8  45.6 NS:    4 VS :  3.61 RMS:   0.66 CORR:  1.000
AVSP:  14.4 7.5  AVDI: 106.0  39.2 NP:    5 VP :  6.75 RMS:   0.94 CORR:  0.999
                 AVDI: 111.7  37.7 NS:    6 VS :  3.82 RMS:   0.97 CORR:  0.999
AVSP:  14.4 7.5  AVDI: 176.7   1.5 NP:    3 VP :  5.13 RMS:   0.07 CORR:  1.000
                 AVDI: 178.0   2.9 NS:    4 VS :  2.80 RMS:   1.06 CORR:  0.859
AVSP:  22.0 5.7  AVDI: 150.0   4.2 NP:    2 VP : 10.17 RMS:   0.00 CORR:  0.000

 Output file is wadati.out