Map
of California & Nevada earthquakes
SAO - San Andreas Geophysical Obs., Hollister, CA, USA
View of SAO equipment building |
1988/01/28 00:00:00 - Present
Latitude: 36.7640
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View of SAO vault |
Location |
Geology |
Vault Conditions
Instrumentation |
Network |
Operation Notes
Noise Characteristics |
Data Availability
- Location:
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Site is located at the San Andreas Geophysical Observatory
in the Hollister
Hills State Vehicle Recreation Area. The BSL first
occupied this site in 1966, with a variety of
geophysical instrumentation. The digital broadband sensors
were installed in 1988.
SAO is a cooperative station with the US National Seismic Network
- Geology:
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Jurassic-Cretaceous Gabilan Granite
- Vault/Borehole conditions:
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The vault is a buried steel culvert liner with a set of three
isolation doors leading to the interior. The pier is poured concrete.
The datalogger and supporting equipment are located in an
air-conditioned structure approximately 50' away and connected via
underground conduits. The seismometers are thermally
insulated with 4" of polyurethane foam.
- Instrumentation:
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Sensor Datalogger Start Date End Date SEED Channels Location Battery Voltage Q4120 2003/01/09 Present AE? Battery Voltage Q935 2001/06/01 Present LE?,UE? Electric Field Dipole (Pb-PbCl or Cu-CuS Anodes) Q4120 1996/02/23 Present VQ?,LQ?,BQ?,UQ? ElectroMagnetics Inc. BF4 Magnetometer Q4120 1995/08/15 Present BT?,UT?,VT?,LT? Internal Temperature Q4120 2003/01/09 Present AK? Internal Temperature Q935 2001/06/01 Present UK? Kinemetrics FBA-23 Accel. (2 g max 1.25 v/g) Q935 1992/06/11 Present LL?,BL?,HL? Motorola MPX201 Pressure Q935 1996/03/07 Present LD? Streckeisen STS-1 VBB Feedback Seismometer Q935 1988/01/28 Present BH?,LH? Streckeisen STS-1 VBB Feedback Seismometer Q935 1992/06/11 Present UH?,HH?,VH? Streckeisen STS-1 VBB Feedback Seismometer Q935 2001/06/01 Present UM? YSI 44031 Thermistor Q935 1996/03/07 Present LK? The SAO site also is home to a continuously operating GPS receiver (SAOB) as part of the BARD network. SAO is also the site of electro-magnetic observations.
- Network:
-
BK (Berkeley Digital Seismic Network)
- Operation Notes: (may not be current)
- This section summarizes major changes in equipment or in instrumentation at SAO.
- 06/15/2004: Changed BH channels sampling rate to 40 Hz.
- 12/07/1999: Q980 upgraded with MSHEAR software.
- 06/04/1998: Replaced STS-1 Z sensor.
- 05/28/1998: Upgraded Q980 with 4 GB disk and ethernet card. Warpless baseplates installed.
- 04/02/1998: Replaced Q4120. Replaced Ashtech receiver.
- 08/21/1997: GPS antenna and Ashtech receiver installed.
- 02/17/1997: Q4120 replaced.
- 05/22/1996: Replaced FBA-23.
- 03/08/1996: Temperature/pressure package installed.
- 11/28/1995: Frame-relay telemetry installed.
- 08/15/1995: EM sensors installed.
- 04/07/1993: The Q980 unit was replaced. GPS clock installed.
- 03/02/1993: Installed NSN satellite system.
- 10/16/1992: Moved STS-1s onto a sand base, from the penny mounting.
- 06/10/1992: The 16-bit PC-based digitizer was replaced with a Quanterra Q980. A Kinemetrics FBA-23 was added.
- 05/23/1991: The STS-1 was upgraded from the BRB response to the VBB response.
- 01/28/1988: An STS-1 with a PC-based datalogger was installed.
- Noise Characteristics:
-
The figures below are cumulative plots of power spectral density (psd)
determined from the broadband channels. In each figure, the vertical
component psd is plotted with blue diamonds, the north component
psd with red squares, and the east component psd with green circles.
The results are presented in the 5 different frequency bands, and
the USGS/Albuquerque low noise model is plotted as a dashed line in each.
The PSD units are in dB (decibel) relative to 1 (m/s**2)**2/Hz. The current
annual plot is updated weekly.
Cumulative PSD results 1999 2000 2001 2002 2003 2004 2005 
- Data Availability:
- BDSN waveforms and associated metadata are available at the
Northern California Earthquake Data Center (NCEDC).
- Map of BDSN stations
- Table of BDSN stations
- BK Information Directory, including
- List of station locations
- List of available channels
- Instrument Response
- Information on Quanterra Timing Errors
- Information on Quanterra 4120 FIR Filter changes - 6/30/2003
- Information on BH sampling rate change - 06/15/2004
- View digital seismograms
Several tools provide access to SEED format data at the NCEDC, both in terms of querying the archives and allowing data requests.- Querying the archives
- Requesting data
Help on using these tools is available.
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Berkeley Seismological Lab
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Copyright 1995-2005, The Regents of the University of California.
Last modified: Wed Jun 25 13:34:08 PDT 2008