- First obtain the software through a license request. For outside users, you also
need to install the PASSCAL utilities. Consult those
documentation for setting up your environment, etc.
- In the Georgia Tech Geophysics lab, add the following lines to your ~/.bashrc file to get Antelope and
necessary PASSCAL utilities:
source /opt/antelope/4.11/setup.sh %Or: source /usr/local/geophysics/antelope/4.11/setup.sh
export PASSCAL=/usr/local/geophysics/passcal
export PASSOFT=${PASSCAL}
export PATH=${PATH}:${PASSCAL}/bin:${PASSCAL}/other/bin
- If you are collecting data in the field. It is always a good practice to make multiple backup
copies of the raw data, straight from the datalogger. For example, I will sometimes have multiple
external hard drives and also keep data on the original Compact Flash cards, if possible.
- Keeping that in mind, we typically create a new directory where we store all the Antelope database
material. Create a new directory and within that directory, create the following directories. FYI, we will
always run commands from this point in the file structure.
mkdir raw_data mseed logs day_volumes
- Next, we create a batch file, which describes the metadata of our network, including station names,
associated dataloggers, station location, and sensor information. THIS IS ONE OF THE MOST IMPORTANT STEPS!
A single entry for a station looks like this:
net CR Costa Rica
sta ACHA 9.8280 -85.2476 0.1350 Alvaro Chavez, CR
time 1/1/2009 00:00:00
datalogger rt130 A024
sensor cmg3esp_100sec 0 t3757
axis Z 0 0 - 1 1
axis N 0 90 - 2 1
axis E 90 90 - 3 1
samplerate 50sps
channel Z BHZ
channel N BHN
channel E BHE
add
close ACHA 12/31/2014
- For this tutorial, download this file and then run this command
to get a parameter file from the information contained in the batch file.
batch2par batchexample > example.par
- You need to replace the column that has some text like rs50spsprs; with 1;.
- Next, download this file and place it in the raw_data directory.
These are files that we extracted from the Reftek dataloggers and are tarred together using the
PASSCAL utility Neo. Fist, untar the files in that directory, and then moving back up, make a list of
the raw files.
- Now we are ready to build our database, which is the backbone for associating all the continuous
data files, storing arrival times of eartquakes, etc. The command here does this:
dbbuild -b exampledb batchexample
- Now let's do some exploring by typing below and clicking on the various buttons that appear. Explore!
- Try going to Site > Graphics > Map and look at the network
- Now let's create a day-long miniseed files from the shorter length files
miniseed2days -v -U -w "day_volumes/%{sta}/%{sta}.%{net}.%{loc}.%{chan}.%Y.%j" mseed/
miniseed2db -v day_volumes/* exampledb
- Building a database from IRIS data
You can accomplish the same thing as the above steps for data from IRIS in 2 simple steps, after submitting an IRIS breqfast request and requesting a dataless SEED volume (metadata) and miniseed data (the miniseed file does not contain station metadata, this is the reason for the dataless SEED volume).
miniseed2days -v -U -w "day_volumes/%{sta}/%{sta}.%{net}.%{loc}.%{chan}.%Y.%j" raw_data_ftp/seismic/*
- At this point, you should be able to look at waveforms, after typing dbe exampledb, go to
Wfdisc > Graphics > Waveforms.
- Next is a series of commands to check everything and create a SEED volume for archival at IRIS.
Enter them line-by-line and check to see that they worked.
Consult documentation provided by IRIS here.
dbfix_calib exampledb
dbversdwf -tu exampledb
dbverify -tj exampledb >& dbverify.out
mk_dataless_seed -v -o CR.12.YYYYDDDHHMM.dataless exampledb
seed2db -v CR.12.YYYYDDDHHMM.dataless
- Building a database from IRIS data
You can accomplish the same thing as the above steps for data from IRIS in 2 simple steps, after submitting an IRIS breqfast request and requesting a dataless SEED volume (metadata) and miniseed data (the miniseed file does not contain station metadata, this is the reason for the dataless SEED volume).
miniseed2days -v -U -w "day_volumes/%{sta}/%{sta}.%{net}.%{loc}.%{chan}.%Y.%j" raw_data_ftp/*
seed2db exampledb.dataless exampledb
- We will now use the database we setup to detect and locate local events. Within the same
working directory, enter the following commands:
mkdir pf
cp $ANTELOPE/data/pf/dbdetect.pf pf
cp $ANTELOPE/data/pf/dbgrassoc.pf pf
cp $ANTELOPE/data/pf/ttgrid.pf pf
cp $ANTELOPE/data/pf/dbevproc.pf pf
- Next, we need to edit the pf/ttgrid.pf preference file to create a local grid for the
gridsearch algorithm centered around our network. Remove the sections dealing with
teleseism and regional events, as we are only interested in local events. After you have edited
it to your satisfaction, enter:
ttgrid -pf pf/ttgrid.pf -time all exampledb > pf/ttgrid
- Have a look at the grid you just created. Is it of sufficient resolution? Enter this to view a map:
displayttgrid pf/ttgrid local
- Next, edit the file pf/dbdetect.pf, which is the automatic detection parameter file.
dbdetect -pf pf/dbdetect.pf exampledb exampledb
- Now we will use the detections on different components and associate them, P versus S, and according to individual events.
First, edit the pf/dbgrassoc.pf file and at a minimum, change the number of minimum stations to 4 (or a value appropriate for your network). When you are ready,
run this command:
dbgrassoc -pf pf/dbgrassoc.pf exampledb exampledb pf/ttgrid
- Finally, we can compute the magnitude of events with this:
dbevproc -p pf/dbevproc.pf exampledb exampledb
- We can edit the automatic picks, as they can sometimes be imprecise.
- This will open various windows, including a new command window and a control panel that wil show a preliminary location
including residuals of the actual picks versus traveltimes predicted by the model used. Click on the button "View Waveforms"
to examine picks for the first event (If you have issues opening dbloc2, try to delete any temp files and/or the .last_id file,etc.)
- The first step is to select the "Vertical channels" and also, in the new command window type:
- This will allow us to pick
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