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MHC - Lick Observatory, Mt. Hamiliton, CA, USA |
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View of the dome at MHC |
1986/09/10 00:00:00 - Present
Latitude: 37.3416
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Typical STS-1 installation |
Location |
Geology |
Vault Conditions
Instrumentation |
Network |
Operation Notes
Noise Characteristics |
Data Availability
- Location:
-
Site is located at the
Lick Observatory atop
Mount Hamilton, and is under the auspices of UC
Santa Cruz. The site was first established in 1887 with the installation
of the first seismic sensors in North America, and has been occupied continuously
since then. Wood-Anderson seismographs were deployed at this site in 1928
and operated until 1993. The first digital broadband instrumentation
was deployed in 1987.
- Geology:
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Jurassic-Cretaceous Franciscan greywacke and greenstone
- Vault/Borehole conditions:
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The vault is located in a room in the east wing of the Lick Observatory.
The piers are reinforced concrete which are isolated from the building.
The seismometer room is isolated from the hallway via two
doors and the datalogger and supporting equipment are in
an adjacent room. The seismometers are thermally insulated
with 4" of polyurethane foam.
- Instrumentation:
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Sensor Datalogger Start Date End Date SEED Channels Location AntennaCurrent Q330HR-GFE 2010/11/17 Present VE? 00 ClockPhase Q330HR-GFE 2010/11/17 Present LC?,VC? 00 ClockQuality Q330HR-GFE 2010/11/17 Present LC?,VC? 00 InputVoltage Q330HR-GFE 2010/11/17 Present VE? 00 Kinemetrics FBA ES-T Accel. (2 g max 10 v/g) Q330HR-GFE 2010/11/17 Present HN? 00 Streckeisen STS-1 VBB Feedback Seismometer Q330HR-GFE 2010/11/17 Present BH?,HH?,LH?,VH? 00 SystemCurrent Q330HR-GFE 2010/11/17 Present VE? 00 SystemTemperature Q330HR-GFE 2010/11/17 Present VK? 00 VCOValue Q330HR-GFE 2010/11/17 Present VC? 00 The MHC site also is home to a continuously operating GPS receiver (MHCB) as part of the BARD network.
- 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 MHC.
- 06/15/2004: Changed BH channels sampling rate to 40 Hz.
- 12/16/1999: Q980 software upgraded to MSHEAR.
- 04/22/1999: Replaced GOES with GPS clock. Upgraded Q980 with 4 GB disk. Installed ethernet card.
- 12/16/1997: Q980 software upgraded to newest version of USHEAR.
- 06/14/1996: Installed GPS receiver on roof of neighboring building.
- 02/23/1996: Barometer and thermometer package installed.
- 11/21/1995: Telemetry moved to frame-relay.
- 06/12/1995: Software upgraded to USHEAR.
- 02/02/1993: Replaced Streckeisen STS-1/UVBB seismometers replaced with a set of STS-1/VBB. The VBB instruments have a 10 Hz high-frequency corner while the UVBB have a 5 Hz corner.
- 10/22/1992: The polarity of the NS channel of the STS-1 seismometer was corrected. From 04/29/92-10/22/92, the polarity of this channel was reversed and the sign of the Sd coefficient reflects this reversal.
- 05/05/1992: Changed line-driver gain on the STS-1.
- 04/29/1992: Replaced the 16-bit PC-based datalogger with the 24-bit Quanterra Q980 system.
- 10/27/1987: The Streckeisen STS-1/UVBB seismometers were installed with a PC-based datalogging system.
- Noise Characteristics:
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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 by channel and time
- Requesting data by event
Help on using these tools is available.
