Dense Travel-Time Tables

The default travel time tables of SeisComP for LOCSAT [4] provide the times in intervals of 1 degree epicentral distance. Thus, the curvature of the travel-time curve at closer distance is not well imaged potentially resulting in wrong locations or missing event solutions. Therefore, the LOCSAT tables, iasp91_scanloc, based on the IASP91 model with higher spacial sampling are added to the scanloc package. The table files are located in $SEISCOMP_ROOT/share/locsat/tables. They may be used along with scanloc and any other module which uses LOCSAT travel-time tables such as scolv [20], scautoloc [13], screloc [21] or even the locator StdLoc [6].

Note

gempa may provide additional travel-time tables as a service based on custom velocity models. Contact us for any related request.

Figure 40: Differences between P-wave travel times in the standard iasp91 tables for LOCSAT and the iasp91_scanloc tables provided with scanloc for an event at 5 km depth.

Application in scanloc

Configure the scanloc parameters association.table and locator.profile with iasp91_scanloc for using these LOCSAT tables in scanloc along with LOCSAT:

# Type of travel-time tables for phase association. May be different from locator.
# Use e.g. libtau or LOCSAT.
association.tableType = LOCSAT

# Name of travel-time table used for phase association. May be different from locator
# profile.
association.table = iasp91_scanloc

# The locator type to use
locator.type = LOCSAT

# The locator profile to use
locator.profile = iasp91_scanloc

Alternatively, you may use the tables along with StdLoc [6].

Application in other modules

In order to visualize the travel times or for using the tables in applications like scolv [20] add the tables to your global module configuration:

ttt.LOCSAT.tables = iasp91_scanloc
LOCSAT.profiles = iasp91_scanloc

More specific parameters may exist along with your application.