SeisComP Location Grid Tuning

What?

The scautoloc module of SeisComP requires a grid file specifying the minimum number of station and within a given distance radius of each specified point where to start locating an event. This grid file allows precise tuning of the possible event origins, and false alarm reduction, by specifying a conservative distance computed for each grid point, considering a given minimum number of station. See https://docs.gempa.de/seiscomp3/current/apps/scautoloc.html#grid-file

./grid4autoloc considers every station with a pick in the last 9 days as active stations (a logic to be refined in future), and compute the distance to twice the number of required stations as the radius from each grid point. A custom query is used to find active stations, the scquery module should be configured with at least basic database access. The station locations are taken via the fdsnws SeisComP module which should be running. The default number of required stations is 4 (i.e. distances thresholds are computed for 8 stations with default safety ratio of 2). However, when the distance is over 3 degrees, the code switches to a so-called teleseismic case where the minimal station number is 9. The default safety ratio of 2 or default number of required stations in normal or teleseismic case (and other things) might be modified in the code if required.

How?

This code required curl, python and numpy to be installed in your system.

Command arguments:

• The first mandatory argument is the author of picks to use for active station search, e.g. scautopick@$HOSTNAME.
• The second mandatory argument is the original grid file to be used for tuning, e.g. $SEISCOMP_ROOT/share/scautoloc/grid.conf.

Assuming default configuration, basic usage might be:

./grid4autoloc scautopick@$HOSTNAME $SEISCOMP_ROOT/share/scautoloc/grid.conf

The result might be written to $SEISCOMP_ROOT/etc/grid-autotune.conf. Setup the following in .seiscomp3/scautoloc.cfg to use the new grid:

autoloc.grid = @SYSTEMCONFIGDIR@/grid-autotune.conf

To have the grid plotted on scolv GUI do:

MYGRID=${SEISCOMP_ROOT}/share/scautoloc/grid.conf
awk '{print $3}'  ${MYGRID}|sort -u|while read D; do mkdir -p ~/.seiscomp3/bna/grid/${D} ; awk '$3~/'$D'/{NL=NL+1;{if($2>180) $2=$2-360} printf "\"%d\",\"grid point %d %.1f km deep\", 1\n",NL,NL,'$D' ;printf "%s,%s\n",$2,$1}'  ${MYGRID}/share/scautoloc/grid.conf >  ~/.seiscomp3/bna/grid/${D}/grid.bna;done

Next?

Next features, still missing, yet to be developed:

1. Safer output only if all scquery, curl, and fdsnws requests are successful, return an error before writing outputs otherwise (will require one more optional command argument).
2. Customise queries for database suffix.
3. You name it.