Map
of California & Nevada earthquakes
CMB - Columbia College, Columbia, CA, USA
Site of CMB vault |
1986/10/25 00:00:00 - Present
Latitude: 38.0345
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STS-1 installation at CMB |
Location |
Geology |
Vault Conditions
Instrumentation |
Network |
Operation Notes
Noise Characteristics |
Data Availability
- Location:
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Site is located on the campus of
Columbia College
in Sonora, California. This site was established to relocate
instrumentation from the JAS1 in Jamestown.
CMB was upgraded with partial funding from the IRIS Consortium and data are archived at the IRIS Data Management Center as well as the NCEDC. CMB is also a cooperative station with the US National Seismic Network.
- Geology:
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Paleozoic marine limestone
- Vault/Borehole conditions:
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The vault is a buried fiberglass cylinder,
eight feet in diameter and
six feet deep. It has a flat top at grade
level with a hatch for entry. The floor
is concrete poured directly on rock.
The datalogger and supporting
equipment are located in an air
conditioned trailer located about 70
feet from the vault and connected via
underground conduits. The
seismometers are thermally
insulated with 4" of polyurethane
foam and the top of the vault is
covered with bark for additional
insulation.
- Instrumentation:
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Sensor Datalogger Start Date End Date SEED Channels Location Battery Voltage Q935 2001/06/01 Present UE?,LE? Guralp CMG-3 Extended BB H Seismometer DWSSN 1989/03/17 1992/06/25 LH?,BH? Guralp CMG-3 Extended BB V Seismometer DWSSN 1989/03/17 1992/06/25 LH?,BH? Internal Temperature Q935 2001/06/01 Present UK? Kinemetrics FBA-23 Accel. (2 g max 1.25 v/g) Q935 1992/06/25 Present HL?,BL?,LL? Motorola MPX201 Pressure Q935 1998/03/05 Present LD? Streckeisen STS-1 VBB Feedback Seismometer Q935 1992/06/25 Present HH?,BH?,LH?,UH?,VH? Streckeisen STS-1 VBB Feedback Seismometer Q935 2001/06/01 Present UM? Teledyde Geotech T210 LP V Seismometer DWSSN 1986/10/25 1989/03/17 LH?,BH? Teledyne Geotech S13 SP V Seismometer DWSSN 1986/10/25 1992/06/25 SH? Teledyne Geotech T200 LP H Seismometer DWSSN 1986/10/25 1989/03/17 BH?,LH? YSI 44031 Thermistor Q935 1998/03/05 Present LK? The CMB site also is home to a continuously operating GPS receiver (CMBB) as part of the BARD network.
- Network:
-
BK (Berkeley Digital Seismic Network)
- Operation Notes: (may not be current)
- This section summarizes major changes in equipment or in instrumentation at CMB.
- 06/15/2004: BH channels sampling rate changed from 20 to 40 Hz.
- 09/19/2000: The STS-1 NS was replaced.
- 08/07/2000: The air conditioner in the trailer is reported to be failing. In addition, analysis of a recent deep teleseism has revealed a problem with the north component, where the amplitude appears to be too small by approximately a factor of 2. This problem seems to have appeared in August 1999.
- 01/06/2000: New BARD GPS monument installed, with Ashtech receiver.
- 12/11/1999: Q980 software upgraded to MSHEAR.
- 05/13/1998: Installed barometer and thermometer set. Replaced GOES clock with GPS.
- 03/04/1998: Q980 upgraded with 4 GB disk and ethernet board. Warpless baseplates installed.
- 09/25/1996: Replaced FBA-23.
- 01/22/1996: Analog telemetry replaced with frame-relay connection with a Vanguard 300 frad.
- 12/09/1993: BARD GPS monument installed, with Ashtech receiver.
- 06/24/1992: A Streckeisen STS-1 and a Kinemetrics FBA-23 were installed with a Quanterra Q980 datalogger, replacing the Guralp CMG-3 and DRS system. This upgrade was partially funded by IRIS and data from this site are contributed to the IRIS Data Management Center.
- 03/17/1989: A set of CMG-3 seismometers with a DRS recording system were installed at this site. The station formed part of the DWWSSN and data from this site were contributed to the Global Seismic Network.
- 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