FMTU: a fast seismic source estimation package

A package to

• estimate seismic full moment tensors from earthquake waveforms
• estimate moment tensor uncertainties
• analyze source types

Installation

Clone and compile

git clone https://github.com/celsoa/fmtu           # celso's branch
cd fmtu
make all    # see next section for options

Compilation options

make cap d=WB               # Compile cap to write a binary file with search data
make cap f=omp              # Compile cap to run in parallel mode (openMP)
make cap d=WB f=omp         # Compile cap to run in parallel and write a binary datafile 
make clean cap d=WB f=omp   # Clean all and compile with all flags

Usage

• A typical command to estimate an earthquake mechanism looks like this

cap.pl EVID [flag1/varA] [flag2/varB] ... [flagN/varX]

• Many flags and values can be passed to FMTU. Which flags and their values depend on the earthquake type, the earthquake signal, etc.
• The following example command will estimate the focal mechanism for the 2008-04-18 earthquake in central USA

cap.pl -H0.2 -P0.6 -S2/5/0 -T35/70 -F -D1/1/0.5 -C0.05/0.3/0.02/0.1 -W1 -X10 -Mcus_15 -m4.5/5.5/0.1 -Y1 -I100000 20080418093700

• For more details and to get started:
  • type cap.pl in the command line and see the flags there
  • see readme_preparation.md and readme_usage.md

Dependencies

Waveform fetching and preparation

Earthquake waveform data can be obtained with the pysep utility, which is a python package for fetching waveform data through FDSN and EIDA webservices, and preparing it for moment tensor estimation. The package can be obtained from one of the following github repositories:

git clone https://github.com/celsoa/sweep           # celso's branch
git clone https://github.com/uafgeotools/pysep      # UAF branch

Signal processing libraries

• The Seismic Analysis Code (SAC) contains routines for dealing with waveform data and can be requested at IRIS: https://ds.iris.edu/ds/nodes/dmc/forms/sac/
• The SAC routine libsac.c deals with filtering waveform data and should be in variable PATH.

Greens functions

• CAP requires a library of precomputed greens functions which are computed with the fk routines
• The latest version fk3.3 can be requested at http://www.eas.slu.edu/People/LZhu/home.html

References

If you use this code in your research, please cite one or all of the following

Estimation of full moment tensors, including uncertainties, for nuclear
explosions, volcanic events, and earthquakes. Journal of Geophysical Research:
Solid Earth, 123(6), 5099-5119. Alvizuri, C., Silwal, V., Krischer, L., &
Tape,C. (2018).

Alvizuri, C., & Tape, C. (2016). Full moment tensors for small events (Mw<3)
at Uturuncu volcano, Bolivia. Geophysical Journal International, 206(3),
1761-1783.

Silwal, V., & Tape, C. (2016). Seismic moment tensors and estimated
uncertainties in southern Alaska. Journal of Geophysical Research: Solid Earth,
121(4), 2772-2797.

These may also be relevant 
Zhu and Ben-Zion, 2013, GJI
Zhu and Helmberger, 1996, BSSA 86, 1645-1641
Zhao and Helmberger, 1994, BSSA 84(1), 91-104