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A wide range of instruments are deployed in the San Francisco Bay Area to monitor crustal deformation. These include continuous GPS receivers, creepmeters, tiltmeters, tensor strainmeters, and dilatometers. These instruments complement the seismic instrumentation by providing a view into the long-term deformation processes.

Both the USGS and the Berkeley Seismological Lab are involved in projects to monitor crustal deformation. An overview of the San Francisco Bay Area project is available.

Creepmeters

Creepmeters continuously monitor near-surface fault movement on the actual fault traces to characterize the rate and nature of fault slip. They can detect changes of about 0.1 millimeters.

• Plots of Creep data in the San Francisco Bay area
  • Last 7 days
  • Last 30 days
  • Long Term data

Tiltmeters

Tiltmeters continuously monitor rotation or tilting in the ground near active faults by precisely measuring either the movement of a pendulum or fluid levels in connected reservoirs (rather like the ring in a bathtub) as the ground tilts. Measurements can easily be made to better than 1 part per billion.

• Plots of Tilt data in the San Francisco Bay area
  • Last 7 days
  • Last 30 days
  • Long Term data

Dilatometers

Dilatometers are strainmeters that measure the volumetric stretching and squeezing of the ground near active faults. Over short time periods they can detect changes of 1-part-per-billion (1 inch in 16,000 miles).

• Plots of Dilatometer data in the San Francisco Bay area
  • Last 7 days
  • Last 30 days
  • Long Term data

Tensor strainmeters

Tensor strainmeters measure the directional stretching and squeezing in the ground near active faults. Over short time periods they can detect changes of 1-part-per-billion (1 inch in 16,000 miles).

• Plots of Tensor strainmeter data in the San Francisco Bay area
  • Last 7 days
  • Last 30 days
  • Long Term data

GPS sites

Global Positioning System (GPS) receivers measure the position of points on the surface of the earth by monitoring signals from a constellation of satellites. Using GPS, it is possible to resolve resolve position changes of order 3 millimeters.

The Bay Area Regional Deformation (BARD) Network consists of 60 continuously operating GPS (CGPS) stations in northern and central California, with special emphasis on monitoring deformation near Parkfield, the Long Valley cauldera, and in the San Francisco Bay area. The primary goal of the network is to monitor crustal deformation across the Pacific-North America plate boundary and in the San Francisco Bay Area for earthquake hazard reduction studies and rapid earthquake emergency response assessment.

• Plots of GPS data
  • GPS Velocities in Central California

Mini-Plate Boundary Observatory

The Mini-Plate Boundary Observatory is a collaborative project of the BSL, the U.S. Geological Survey (USGS) at Menlo Park, the Department of Terrestrial Magnetism at Carnegie Institution of Washington (CIW), and the IGPP at UC San Diego (UCSD). It augments existing infrastructure in central California to form an integrated pilot system of instrumentation for the study of plate boundary deformation, with special emphasis on its relation to earthquakes. This project is partially funded through the EAR NSF/IF program with matching funds from the participating institutions and the Southern California Integrated Geodetic Network (SCIGN).

• Plots of Mini PBO data in the San Francisco Bay area
  • Brisbane (Last 7 days | Last 30 days )
  • Marin Headlands (Last 7 days | Last 30 days )
  • Ohlone (Last 7 days | Last 30 days )
  • Ox Mountain (Last 7 days | Last 30 days )
  • St. Vincents (Last 7 days | Last 30 days )

Berkeley Seismological Laboratory
202 McCone Hall, UC Berkeley, Berkeley CA 94720-4760
Questions and comments to www@seismo.berkeley.edu
Copyright 2003, The Regents of the University of California.
Last modified: Thu Dec 6 15:18:42 PST 2007