CDSEIS reads seismic data from SEED volumes and writes SAC (or AH) files for analysis. Unlike other SEED-reading tools, the files that it outputs are event oriented, cut around the arrival times of specific (user-tailored) phases, and named using event-specific names. The files have event and station information populating the file headers. The result is a collection of traces that is immediately available for analysis.
To select waveforms for analysis, CDSEIS uses a text index (log file) made by MAKELOG for each SEED volume (or collection). The logs summarize the waveform start and stop times and associates each waveform with an event. The user specifies various search parameters to identify the desired seismograms. Once the desired time windows are identified, they can then be read directly from the SEED volume. The use of an index file results in greatly increased speed compared to searching through the entire SEED volume to find the desired time series.
CDSEIS uses a command language (similar to PLOTXY, etc.) to decide which
waveforms to extract. The basic idea is to define a number of search parameters
that are used to select which seismograms to read. The defaults defined for
most of the parameters minimize user input. CDSEIS reads the search commands
and outputs either a list of seismograms matching the search criteria (SCAN
option) or the seismograms themselves (READ option).
./configure ## run configuration - to get help, ./configure --help
make ## makes cdseis, makelog, make_tt
make test ## extracts SAC traces from a SEED volume for testing
make install ## install programs in binary directory of choice
The configure step tries to find the SAC libraries (for cdseis) and the Buland & Kennett tau-p routines (for make_tt). If they are not available, or in an unexpected place, compilation will either fail (cdseis) or will produce no output (make_tt). If a failure occurs, use
./configure LDFLAGS='-L<directory-with-libsacio.a>'
or
./configure SACAUX=<directory-with-SAC-aux-files>
to help the configure process find the SAC libraries.
After installing CDSEIS, print the documentation to the screen by:
man cdseis
or
man makelog
To get hard copy, use
man -t cdseis > cdseis.ps
or
groff -man -t cdseis.man > cdseis.ps
and view cdseis.ps with your favorite PostScript reader. Use similar methods to get makelog documentation.
Type
make uninstall
to remove the programs and travel time data files.
There are three commonly used programs in the src directory: makelog, make_tt and cdseis itself.
-
MAKELOG reads a list of SEED volumes and makes an ASCII log file of all waveform start and stop times, associating each waveform with an event. The event list is either taken from the SEED volume itself (if it contains one), or from an external catalog provided to the program. Possible catalog formats are the Global CMT .ndk format or a file with one entry per line (see the file test/events.dat for an example or read the program program for format details).
-
CDSEIS reads the log file(s) created by MAKELOG, accepts a variety of search parameters in an interactive mode, and either creates a list of available waveforms (without reading data) or retrieves requested waveforms from the SEED volume (or a CD).
-
MAKE_TT makes up a set of approximate phase travel time tables from the Kennett and Buland tau-p routines. CDSEIS uses these tables to calculate expected arrival times for extracting data around major phase arrivals. The routine uses the subroutine interface to tau-p; you need to have a working version of it to compile this program.
The programs can be compiled by typing: make all
The programs can be tested by typing: make test
The programs can be installed by typing: make install
Some example (approximate) travel time curves are given in files
beginning with tt_. They will be installed in a library directory associated
with CDSEIS (see cdseis.in.scan for the location; when `make install' is done,
you'll get a report of the location too).
You will need to use MAKELOG to create a log file for new SEED volumes that you receive. MAKELOG is now fairly robust in dealing with SEED volumes, and is unlikely to fail, but it is possible that MAKELOG could crash on a subsequent SEED volume because of some peculiarity associated with new data. After running MAKELOG always check the log file, makelog.log, for errors and warnings.
Originally, MAKELOG read an entire cdrom and made an ASCII log file of all waveform start and stop times, associating each waveform with an event. On a SUN sparcstation this took about 1-2 hours for each cdrom. This program also read all the station corrections and instrument response poles and zeros, and reported errors and warnings to standard output when it does not recognize the format. CONVERTLOG essentially tidied up the output from this program. (This version of MAKELOG is in the src/cd directory for historical completeness.)
CONVERTLOG (in src/cd for historical completeness) reads a cdrom log created by the old, CD version of MAKELOG, removes trailing blanks to reduce the file size, and assigns a unique event designation to each event.
Logs created by the old MAKELOG and CONVERTLOG for almost all CDs that were ever distributed by seismological agencies are supplied in the directory logfiles, in files named files log*. The first CD put out by the NEIC was distributed with integer bytes in the order that is standard for DEC computers and has the number 5033 stamped on the front of the disk. It was also distributed using the UNIX convention and has the number 5054 stamped on the front. As far as I can tell these are identical except for the order of the bytes in each integer. The log file 'log5033' works for either disk. All subsequet CD's use the UNIX convention. CDSEIS reads 5054 correctly if the variable 'byteswap' in the main program is set to '.false.' and will read 5033 properly if 'byteswap' is set to '.true.'.
Though they all may be overridden in the cdseis input file, you may wish to change the default values of some of the parameters to suit your particular needs. The default values are all set in data statements in the main program (cdseis.f). In particular, expert programmers might wish to change the default directories for the phase files, and catalog files, and the cdroms, which are in variables phsdir, logdir, and cddir.
COMM This test file extracts events suitable for P receiver function analysis
COMM from the SEED volumes described in CDLV-RF.log. All events between 30
COMM and 95 degrees with magnitudes between 5.8 and 10 are selected. CDSEIS
COMM outputs traces in a time window 2 minutes before the P arrival and 3
COMM after it for each station. Three-component seismograms are produced,
COMM labeled with the station name, event name, p, and channel name (*h[enz]),
COMM depending on the sample rate (between 1 and 100 sps).
LDIR ./
PDIR ../tt
CDIR ./seed
ODIR /tmp
RANG 30, 95
QMAG 5.8, 10.0
WIND -2 3
PHAS tt_p
SRAT 1 100
COMP 1
FILE st ev p ch
LOGF CDLV-RF.log
STAT
READ
QUIT
The input file above illustrates a typical use of CDSEIS in a research
project to get the data from repository format (SEED) into an analysis format
(SAC). A list of the available seismograms could be obtained by replacing the
READ command with the SCAN command.
comm This extracts three-component seismograms starting before the P wave
comm arrival to 20 minutes after it, for an event on 28 Aug. 1985. It
comm reads data from the CDROM labeled 5461.
dmin 85 8 28 0 0
dmax 85 8 28 23 59
cdir /cdrom
logf log5461
srat 2 16
phas tt_p
wind -2 20
file ev ch
otyp sac
wtyp n
stat
comp 1
read
quit
This gives 3 files for vertical, north and east components of intermediate- period seismograms from a deep-focus earthquake. The vertical component seismograms can be displayed using 'read *.ihz' if you have SAC running. Make sure CDROM 5461 is mounted at the directory /cdrom. You can get a list of the seismograms by replacing 'read' command by by 'scan'.
(cd DDIR ; ls *.seed | \
makelog -cat cmt DDIR /usr/share/data/CMT/cmtdat ) > logDDIR
This tells makelog to scan all of the SEED volumes in the directory DDIR ending
with the name *.seed and to find all of the events associated with data
traces in the SEED volume with earthquakes in the copy of the CMT catalog in
/usr/share/data/CMT/cmtdat. The resulting log file is named logDDIR. To
extract data, you would run cdseis with cdir DDIR and logf logDDIR. (See
the Global CMT Project for CMT
catalog download information.)
CDSEIS was originally written to extract data from GDSN CD-ROMs. Subsequently, it was expanded to work with SEED-oriented datasets. CDSEIS was written by Peter Shearer (1989) to run on a Macintosh. Ken Creager added several options and modified the code to run in a UNIX environment. Tom McSweeney wrote the routine write_ah.c. Doug Wiens wrote an early version of the instrument response reader. George Helffrich added SAC output and implemented reading of SEED volumes, and is responsible for continued maintenance of CDSEIS. Thanks to the IRIS DMC (and its' many software developers) for providing rdseed code, from which EVALRESP-compatible response writing was derived.
Please report bugs, suggestions, and comments to G. Helffrich.
- The time corrections were given, improperly, as either the first or last time correction in the station log. It now properly interpolates the given time corrections to the time of the first sample in the seismogram.
- Fix bug where gain is returned incorrectly if 3 component SP data is followed by LP.
- ##Data output in AH format now has gain reported in counts/meter, instead of counts/micrometer.##
- CDSEIS now reads the band (short-period, long-period, etc.) from the station log, and puts this in the filename if requested. The channel name in the headers is converted to SEED format (eg LHZ for long-period high gain, vertical). Channel used to be called VERT for vertical.
- SCAN will output a subset of the log file in the log-file format.
- Add COMM, * commands for comments in input files.
- Make STAT output prettier, align.
- Comment out some debugging code that was left active. It printed stuff on range/midpoint searches.
- New station codes. Made changes to SROSTA2 and stalist. In the present version, this code isn't used, but one of these may form the basis of the subroutine that Peter Shearer was asking for. Instead, the station log is parsed to obtain the station names, locations and data format information on the CD being processed. I'm somewhat chary of the instrument locations in this list simply because a lot of it is typed in by hand and there is a potential of screwing up the locations (thus the ckstainfo program). I checked the ones I added, but not the original ones.
- Fix bug on EOF -- causes infinite loop. Proper command is QUIT not STOP.
- Moved nonblank length and file name subroutines into cdsubs.f -- used by write_sac.f
- Omit blank first output line in CONVERTLOG.
- Change julian date handling to eliminate 1995 restriction.
- Obtain station info from the data log when the data is being retrieved. This change was needed because on some CDs the same station has different GDSN ID numbers, and the same GDSN ID number refers to different stations on different CDs.
- OTYP=10 added and set to default: Get any available orientations. If OTYPE=5 during a search, all traces (both horizontals & verticals) are listed. If doing a READ, only the vertical component is extracted. Thus, you can't match up a SCAN listing with the result of a READ if OTYPE=5. Adding OTYPE=10 lets you see and ask for any data during either READ and SCAN, and lets you get only vertical component data if OTYPE=5. In other words, what you see is what you get whether you SCAN or READ.
- Fix zero division bug if you extract data that is flatlined at zero.
- Decode new data formats: 1) Grafenberg; 2) Echery; 3) GEOSCOPE 24-bit.
- Make MAKELIST terminate gracefully if an EOF is given.
- Make MAKELIST dump out a list of stations and locations encountered on the CD processed to the output file.
- Name the new CDs depending on range of data.
- SAC output format.
- Poles and zeroes output in SAC format.
- Comments are read from cdrom and passed to output files
- Able to extract from SEED volumes
- Station elevation and event magnitude in SAC output
- Make CDSEIS exit gracefully if EOF on input given.
- Fix pole-zero response information parsing and output.
- Add network and instrument type to station type information.
- Improve handling of time-dependent channel descriptions (bug fix).
- Handle new seed data block types (M, Q, etc.)
- Make g77 & gfortran compatible.
- Put network name and LOCID into SAC output files
- Added EVALRESP response output.
- Made error messages about invalid input more descriptive.
- Change log file format to recognize that different LOCIDs with the same sample rate may be present at one station. At present, if different LOCIDs have the same sample rate, they can't all be listed in the log file. (The "seed" designator should also be changed at the same time to an identifier that takes up less space.)
- Change SAC output so that freq-amp-phase response information may be written out in SAC's FAP file format.
Keep wishing for no bugs in the code.