Antelope 4.10+ Tutorial for creating, managing, and utilizing databases
Part 4
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Event detection and association
1.
Set up the parameter files:
The original files for these programs need to be copied initially but this stepped can then be
skipped.
mkdir pf
cp $ANTELOPE/data/pf/dbdetect.pf pf (Contains the filters)
cp $ANTELOPE/data/pf/dbgrassoc.pf pf
cp $ANTELOPE/data/pf/ttgrid.pf pf (Contains the vel model and parameters)
2.
Create the travel time tables:
Change the ttgrid.pf file to reflect station spacing, network location, velocity model etc.
ttgrid –pf pf/ttgrid.pf –time all AprilNicoya >! pf/ttgrid
3.
Run detection programs:
STA/LTA detecter with parameters to control filter
Change dbdetect to read BHZ and 1
dbdetect –pf pf/dbdetect.pf AprilNicoya AprilNicoya
4.
Run event association and initial location program
Revise dbgrassoc.pf
vim dbgrassoc.pf
change orbassoc to dbgrassoc and remove _?
set minimum number of stations to 5 for local
change tele to tele_slow
Initial arrival associator and event locator
dbgrassoc –pf pf/dbgrassoc.pf AprilNicoya AprilNicoya pf/ttgrid
Note 1: To clear the detections made while practising or before the database is complete, just
delete the origin, assoc, orgerror, detection, arrival, and trigger files from the /db directory. The
will be recreated when you rerun the detection programs.
Note 2: Quick view of locations
dbmapevents AprilNicoya JUDI 5
mv AprilNicoya.* db/.
5.
Calculate magnitudes for dbgrassoc events and get files set up for dbloc2
Copy dbml.pf from $antelope/data/pf
vim pf/dbml.pf
Replace default stations with broadband Nicoya stations (BHZ)
and info from ~/deshon/pf/dbml.pf
dbml –p pf/dbml.pf –make_magtables AprilNicoya
mv AprilNicoya.* db/.
6.
Fix up any problems
dbverify –I detection AprilNicoya >&! verify.3
Most other errors in the db at this time would be removed during event review using dbloc2
7.
Review data
Review and create new filters
cp /Users/hdeshon/.dbpickrc ~/.
cp /Users/hdeshon/*pf ./pf/.
dbloc2 –p pf/dbloc2.pf AprilNicoya (To view located events and relocate events; detections are
located in the origin table. See notes below on how this program works.)
Note 1: On opening dbloc2, you may find duplicate arrivals where one is marked P and the other
‘D or del’ for arrivals grouped into events. Also, when trying to move onto the next event, dbloc2
actually moves to the next ‘D or del’. ‘D or del’ are the unassociated arrivals or detetctions from
the STA/LTA detector and make using dbloc2 a pain. You can remove triggers that do not get
associated with an event ‘D or del’ in arrival table using the following:
dbnojoin AprilNicoya.arrival assoc | dbdelete Once you do this however, they disappear forever! You may want to create a backup of the db
directory before running this command.
Information for dbloc2:
 If two events show up on the same screen make sure when locating you are only using the
arrivals for one event. Also make sure that each event is the right origin id-you may have to
change the origin id for the second event by clicking on the origin id number and using the
new event option.
 If you get an iterations error, change the max iterations bar. If this doesn't work, check that
the assigned error bars are reasonable for each P and S pick.
 You want to click on the preferred location button for the best event. Save this event, chop the
automatic, delete the trial events (unless you want to save them), and save the associated event
if there is one.
 After picking arrivals for an event and relocating the event, click the next button to move on.
This may go back to the new location you just picked so make sure you are picking arrivals
for an event that has not been relocated and associated. Generally all this means is clicking on
the next button twice rather than just once.
 Filters can be created or changed in the .dbpickrc (antelope home directory) or you can create
your own filter file in the local directory.
MOUSE BUTTON
Left-Click
Right-Click
Middle-Drag
Shift-Left-Click
Shift-Right-Click
Left-Click-on-Station-Label
Left-Drag-across-Station-Label
Left-Click-on-Arrival-Flag
Shift-Left-Click-on-Arrival-Flag
Control-Shift-Left-Click-on-Arrival-Flag
Control-Left-Click-on-Arrival-Flag
Middle-Click-on-Arrival-Flag
Right-Click-on-Arrival-Flag
ACTION
Time Scroll to the left
Time scroll to the right
Time scroll left or right
Time zoom in
Time zoom out
Select/Deselect station
Select/Deselect station
Adjust arrival time
Adjust arrival time uncertainty
Adjust arrival amplitude-period
Show arrival measurements
Phase code menu
Arrival menu