UCVM Utah

Overview

A powerful capability of UCVM is its ability to be extended beyond the state of California. To show how this can be done, UCVM was setup for the Salt Lake City region of northern Utah. The WFCVM velocity model was used as the basis for this implementation.

The WFCVM covers the Wasatch Front region of north-eastern Utah. It was developed by Harold Magistrale and is posted for download by the Utah Geological Survey. The codes and model structure are based upon Magistrale's prior work on CVM-S.

Datasets

UCVM Utah digital elevation model.

File:Ucvm utah vs depth0.png

Vs map at depth 0m.

File:Ucvm utah vs depth2000.png

Vs map at depth 2000m.

UCVM requires this information for any new coverage region:

• digital elevation model
• Vs30 map
• one or more community velocity models for the region that can be queried by geographic coordinates

For this Utah implementation, the following dataset were used:

• DEM: ETOPO1 1 min resolution world-wide elevation data
• Vs30: Wald's global Vs30 database
• CVM: Magistrale's WFCVM

Setup Steps

General steps used to setup this new region:

• Gather DEM and Vs30 data in ArcGIS GridFloat format
  • ETOPO1 is already in this format
  • Vs30 data was converted from GMT grid format to ArcGIS Gridfloat using ./scripts/vs30/convert_wald.sh (requires GMT)
• Extract UCVM DEM/Vs30 etree using grd2etree
• Create model interface for WFCVM. Involved modifications to WFCVM to convert the executable to a static library.
• Recompile UCVM.
• Create new configuration files
  • UCVM model conf file ./model/ucvm_utah.conf with projection information (UTM-12 used for this example)
  • UCVM application conf file ./conf/aftershock/ucvm_utah.conf with path to WFCVM model directory

Download WFCVM

The original distribution is available for download from Utah Geological Survey.

A modified version of WFCVM (converted to static library for UCVM) may be checked out from SVN with these commands:

svn co https://source.usc.edu/svn/wfcvm/trunk

No released, prepackaged distribution of this software currently exists.

References

1. Magistrale, H., S. Day, R. Clayton, and R. Graves (2000). The SCEC southern California reference 3D seismic velocity model version 2, Bull. Seism. Soc. Am. 90 (6B), S65-S76.