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Installation of strainmeter at OHLN Courtesy of the USGS

2001/10/05 00:00:00 - Present Latitude: 38.0063 Longitude: -122.2730 Elevation: -0.50 meters

Completed OHLN site, with GPS monument

Location | Geology | Vault Conditions
Instrumentation | Network | Operation Notes
Noise Characteristics | Data Availability

Location:

OHLN is one of five sites installed as a pilot test for the Plate Boundary Observatory, known informally as the Mini-PBO project. This site is known as SFOHL in the USGS Low Frequency Network and is located in Ohlone Park, in Hercules, CA.

Geology:

TBD

Vault/Borehole conditions:

The OHLN borehole was the first of the MiniPBO sites to be drilled and was installed on 7/16/2001. The strainmeter is emplaced at a depth of 670.5 ft and the seismometer is at a depth of 645.5 ft. This figure shows the location of equipment in the borehole.

Instrumentation:

Sensor	Datalogger	Start Date	End Date	SEED Channels	Location
Battery Voltage	Q4120	2003/06/30	Present	UE?,LE?
Internal Temperature	Q4120	2003/06/30	Present	UK?
Mark Products L-22 Horizontal Geophone	Q4120	2001/10/05	2003/06/30	BP?,LP?,EP?
Mark Products L-22 Horizontal Geophone	Q4120	2003/06/30	2004/01/06	LP?,BP?,EP?
Mark Products L-22 Horizontal Geophone	Q4120	2004/01/06	2005/08/26	BP?,EP?,LP?
Mark Products L-22 Horizontal Geophone	Q4120	2005/08/26	2005/10/21	BP?,LP?,EP?
Mark Products L-22 Horizontal Geophone	Q4120	2005/10/21	Present	BP?,EP?,LP?
Mark Products L-22 Vertical Geophone	Q4120	2001/10/05	2003/06/30	BP?,EP?,LP?
Mark Products L-22 Vertical Geophone	Q4120	2003/06/30	2004/01/06	BP?,LP?,EP?
Mark Products L-22 Vertical Geophone	Q4120	2004/01/06	2005/08/26	BP?,EP?,LP?
Mark Products L-22 Vertical Geophone	Q4120	2005/08/26	2005/10/21	LP?,EP?,BP?
Mark Products L-22 Vertical Geophone	Q4120	2005/10/21	Present	BP?,EP?,LP?
Paroscientific 8WD Digital Pressure Meter	PDPM	2002/07/20	Present	LD?
Sacks 3-component Tensor Strainmeter	Q4120	2001/10/05	Present	LS?,BS?,HS?,US?,VS?
Setra Systems Model 270 Barometer	Q4120	2001/10/05	2003/06/30	LD?
Setra Systems Model 270 Barometer	Q4120	2003/06/30	Present	LD?

As a Mini-PBO site, OHLN is also home to a continuously operating GPS receiver (OHLN) as part of the BARD network.

Network:

BK,UL (Mini PBO Network and USGS Low Frequency Network)

Operation Notes: (may not be current)

This section summarizes major changes in equipment or in instrumentation at OHLN.

Noise Characteristics:

No noise information for OHLN is available at this time.

Data Availability:

BDSN waveforms and associated metadata are available at the Northern California Earthquake Data Center (NCEDC).

• Map of Mini-PBO stations
• Table of Mini-PBO stations
• BK Information Directory, including
  • List of station locations
  • List of available channels
    • Year/month/day format
    • Year,doy format
• UL Information Directory, including
  • List of station locations
  • List of available channels
    • Year/month/day format
    • Year,doy format
• Instrument Response
  • BK - SEED format
  • UL - SEED format
  • BK Simplified Responses
• Information on Quanterra 4120 FIR Filter changes - 6/30/2003

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
  • SeismiQuery at the NCEDC
  • NetDC Request Form
• Requesting data
  • NetDC Request Form

Help on using these tools is available.