/Vespagram

Velocity spectrum program: constrain ray parameters or back-azimuth with array method.

Primary LanguageC

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NOTICE!!! THIS PROGRAM COMES WITH NO WARRANTY, TO THE EXTEND PERMITED BY LAW!

Vespagram

  • To execute velocity spectrum analysis (VESPAGRAM or VESPA)

Basic principles

Rost S, Thomas C (2002) Array seismology: methods and applications. Rev Geophys 40:1008. doi: 10.1029/2000RG000100

Dependencies

  • Linux or Mac OS platform
  • SAC(Seismic Analysis Code, here, version 101.6a)
  • GMT(The Generic Mapping Tools, here version 5.3.1)

Installation

  • After downloading the C programming source code just run "make" to compile it, and you will get the executable binary file "vespa", and copy it in your bin directory if you wish.

Usage

vespa sacfile.lst t1 t2 fre_low fre_high ID<baz/slow> baz/slow slow_low/baz_low slow_high/baz_high slow_step/baz_step Nth_root output_file

  • NOTICE!!!
Here, slowness actually means horizontal slowness or ray parameter.
parameter mean
sacfile.lst file containing names of SAC format files
t1 begin time of doing vespagram
t2 end time of doing vespagram
fre_low low limitation of corner frequency of SAC files
fre_high high limitation of corner frequency of SAC files
ID<baz/slow> "baz": fixed back-azimuth and scanning slowness; "slow": fixed slowness and scanning back-azimuth
baz/slow if back-azimuth fixed, its specific fixed value; or slowness fixed, its specific fixed value
slow_low/baz_low if back-azimuth fixed, low limitation of scanning slowness; or slowness fixed, low limitation of scanning back-azimuth
slow_high/baz_high if back-azimuth fixed, high limitation of scanning slowness; or slowness fixed, high limitation of scanning back-azimuth
slow_step/baz_step if back-azimuth fixed, step length of scanning slowness; or slowness foxed, step length of scanning back-azimuth
Nth_root stacking method, specially, it means linear stacking when N is 1
output_file file name of outputting results

Example

1️⃣ The seismic stations mapping of this array.

STATIONS

2️⃣ SAC format data recorded by this seismic array.

SAC

3️⃣ Find the back-azimuth with beam-forming method

4️⃣ Fix the back-azimuth with 116 degrees and scan horizontal slowness or ray parameters.

RESULTS

Contribution