Map
of California & Nevada earthquakes
ARC - Humboldt State University, Arcata, CA, USA
Founders Hall, HSU |
1992/05/28 19:48:00 - 2001/08/02 00:36:00
Latitude: 40.8777
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Typical STS-2 installation |
Location |
Geology |
Vault Conditions
Instrumentation |
Network |
Operation Notes
Noise Characteristics |
Data Availability
- Location:
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ARC was located on the campus of
Humboldt State University,
in cooperation with the
Geology Department.
The site was established in 1948 with the installation of Sprengnether
sensors. Wood-Anderson seismographs were installed in 1952 and
operated until 1993. The digital broadband equipment was installed
in 1992.
The site was relocated in 2001 to station JCC.
- Geology:
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Quaternary Sandstone
- Vault/Borehole conditions:
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The instruments are sited on the ground floor of
Founders Hall at Humboldt State University.
The digital instrumentation is located on the same concrete
pier as the Wood-Anderson seismometers, in a room at the
northwest corner, which is isolated from the hallway via
two doors. The seismometers are thermally insulated with
4" of polyurethane foam. An adjoining room contains
the datalogger and supporting equipment.
- Instrumentation:
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Sensor Datalogger Start Date End Date SEED Channels Location Battery Voltage Q935 2001/06/01 2001/08/02 LE?,UE? Internal Temperature Q935 2001/06/01 2001/08/02 UK? Kinemetrics FBA-23 Accel. (2 g max 1.25 v/g) Q935 1992/05/28 2001/08/02 LL?,BL?,HL? Streckeisen STS-2 VBB Tri-Axial Seismometer Q935 1992/05/28 2001/08/02 UH?,VH?,LH?,BH?,HH? Streckeisen STS-2 VBB Tri-Axial Seismometer Q935 2001/06/01 2001/08/02 UM? - Network:
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BK (Berkeley Digital Seismic Network)
- Operation Notes: (may not be current)
- This section summarizes major changes in equipment or in instrumentation at ARC.
- 08/02/2001: With the successful installation of the BDSN station JCC, the BSL closed ARC after several months of simultaneous recording. The BSL thanks HSU for a long and productive collaboration.
- 12/12/1999: Q980 software upgraded to MSHEAR.
- 04/01/1999: Quanterra GPS QTS1 clock replaced by Quanterra GPS QTS2 clock and V100 FRAD replaced with V320 FRAD. Q980 disk upgraded to 2 Gb and an ethernet card installed.
- 02/20/1997: GOES clock replaced by a Quanterra GPS QTS1 clock.
- 03/08/1996: Analog telemetry replaced with frame-relay connection.
- 05/12/1995: Q980 software upgraded to USHEAR.
- 01/15/1993: Wood-Anderson torsion instruments removed.
- 05/26/1992: A Streckeisen STS-2 and a Kinemetrics FBA-23 were installed with a Quanterra Q980 Datalogger and a Truetime GOES clock.
- 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