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Min-Hung Shih 10/13/2011 Ver. 0.3. Auto-location and manual location in Antelope. 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
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Min-Hung Shih 10/13/2011 Ver. 0.3 Auto-location and manual location in Antelope
Quick View • Run dbdetect to execute STA/LTA detectors on the waveforms • Run dbpickon 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
dbdetect • dbdetect runs STA/LTA algorithm on seismic data to determine the arrival times of seismic energy.
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
STA window LTA window
dbdetect.pf Globel parameters reject station & channel Design multi-filter for individual station & channel Design multi-filters Assign station & channel
ttgrid • Compute a travel time grid file
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
dbgrassoc • dbgrassocspatial grid search based associator/locator
dbgrassoc.pf Put your grid name here !! define the parameters for each grids in grid_file
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.
dbloc2- Interactive hypocenter location • >dbloc2 dbname