USGS Bay Area Velocity Model Release 05.1.0
Tom Brocher (USGS Menlo Park), Cliff Thurber (Univ. of Wisconsin)
Updates
- 2005, November - Initial release
Description
This release of the USGS Bay Area Velocity Model includes both a detailed model and an extended (regional) model. The extended model extends the velocity model to approximately 650 km x 330 km x 45 km. Note that the extended model contains much less detail than the detailed model, hence the names. Additionally, the detailed model has been extended down to a depth of 45 km (see the description of the fault block model for geographic coverage).
The detailed model can be used without the extended model, but not vice versa. In other words, if you only want to use the detailed model you do not need to download the extended model, but if you want to use the extended model, you must download BOTH the detailed and the regional model. To enable use of the extended model, simply supply the filename of the extended model in addition to the filename of the detailed model when setting up the queries (see cencalvm software documentation).
The gzip compressed database file for the detailed model is 1.6 GB, uncompressed it is ~8.9 GB. Similarly, the extended model is 1.0 GB compressed, and ~6.5 GB uncompressed.
The resolution of the models is variable with the following specifications:
- Detailed model
Elevation1 Horiz. Resolution Vertical Resolution z > -400m 100m 25m -400m > z > -3200m 200m 50m -3200m > z > -6400m 400m 100m -6400m > z > -45000m 800m 200m - Transition from detailed model to extended model. This is
a region 3.2km in width surrounding the detailed model. It is
part of the extended model.
Elevation1 Horiz. Resolution Vertical Resolution z > -3200m 200m 50m -3200m > z > -6400m 400m 100m -6400m > z > -45000m 800m 200m - Extended model
Elevation1 Horiz. Resolution Vertical Resolution z > -6400m 400m 100m -6400m > z > -45000m 800m 200m
Changes from release 05.0.0
- Improved top surface for the Mafic lower crust
- Holocene Bay Mud changed to Holocene & Quaternary alluvium. This is more appropriate given the resolution of the model.
- 2x greater resolution for -6400m < z < -3200m (800m/200m resolution to 400m/100m resolution).
- Model now goes down to z=-45km