The purpose of this tutorial is work with a SEED data volume, which is usually obtained from the IRIS DMC or the Orfeus Data Center.

For this tutorial, you will unpack a SEED volume into SAC files, enter the earthquake source parameters into the SAC headers, remove the instrument response to yield ground velocity in units of m/s, and finally rotate the traces to vertical, radial and transverse components of ground motion.

These shell scripts required are IDOEVTIDOROT and IDODEC

You will work with the SEED volume 20020618.5710

Running the scripts

Read the scripts carefully to see what they do. Similar scripts are used in the Receiver function tutorial.

mkdir Sac
cd Sac
rdseed -f ../20020618.5710 -R -d -o 1
cd ../GOOD
cd ..
mkdir MFT
cd MFT
do_mft ../FINAL/*

We first create a location for unpacking the SEED volume. The program rdseed is used for the unpacking. The result are the response files in evalresp format as well as the sac files. The script puts the event information into the headers of the sac files, removes the instrument response, and places these files into the parallel directory GOOD. This is where the traces are review to see if they are OK. The script IDOROT performs the rotation and places the rotated traces into the parallel directory FINAL. The script IDODEC resamples the trace to 0.25 seconds for use with he multiple filter analysis program (long period surface-wave analysis does not require 20 or 40 Hz sampling rates. The decimated versions are placed into the parallel directory FINAL.DEC. Finally a multiple filter analysis directory is created and group velocity analysis is started.