1. Auto-location and manual location in Antelope
Min-Hung Shih
10/13/2011 Ver. 0.3

2. Quick View Run dbdetect to execute STA/LTA detectors on the waveforms
Run dbpick on the database to modify picks
Run ttgrid to make a grid file
Run dbgrassoc to produce origin and event tables
Run dbloc2 on the database to modify picks and calculate earthquake locations

3. dbdetect step1 step2 step3
dbdetect runs STA/LTA algorithm on seismic data to determine the arrival times of seismic energy.
step1
Copy parameter file on local directory
>pfcp dbdetect your_directory
step2
Edit dbdetect.pf
>vi dbdetect.pf
step3
Execute dbdetect
>dbdetect -arrivals -pf pffile dbin dbout

4. STA/LTA algorithm STA/LTA 運算程序，就是利用所謂的「短時窗信號平均值」與「長時窗信號平均值」的比值，判讀地震訊號
STA為Short Time Average之縮寫，也就是短時窗信號平均值，另一要素為LTA，是Long Time Average之縮寫，也就是長時窗信號平均值，當STA除以LTA之值大於設定值(threshold)時，即視為地震訊號

5. STA window
LTA window

6. dbdetect.pf Globel parameters reject station & channel
Design multi-filter for individual station & channel
Design multi-filters
Assign station & channel

7. dbpick - check arrivels

8. ttgrid step1 step2 step3 step4 Compute a travel time grid file
Copy paraneter file on local directory
>pfcp ttgrid your_directory
step2
Edit ttgrid.pf
>vi ttgrid.pf
step3
Execute ttgrid
>ttgrid -pf ttgrid.pf time all db > grid_file
step4
Display the grid
>displayttgrid grid_file grid_name

9. grid name ( remember the grid names and how many grids you have !! )
ttgrid.pf
Design grid 2
Deisgn grid 3
Design grid 1
Design grid 4

10. displayttgrid (check your grid)

11. dbgrassoc step1 step2 step3
dbgrassoc spatial grid search based associator/locator
step1
Copy paraneter file on local directory
>pfcp dbgrassoc your_directory
step2
Edit dbgrassoc.pf
>vi dbgrassoc.pf
step3
Execute dbgrassoc
>dbgrassoc -pf dbgrassoc.pf dbin dbout grid_file

12. dbgrassoc.pf define the parameters for each grids in grid_file
Put your grid name here !!
define the parameters for each grids
in grid_file

13. Output files of dbgrassoc
db.origin - hypocenter parameters
db.event - the preferred origin for an event
db.arrival - phase, time of the seismic arrivals
db.assoc - connects arrival to origin, list travel time residuals, etc.

14. dbloc2 - Interactive hypocenter location
>dbloc2 dbname

15. Practice !!!