OHLN - Ohlone Park, Hercules, CA, USA
|Station Name||OHLN (OHLN)|
|In Operation||2001/10/05 00:00:00 - Present|
LocationOHLN 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.
NetworkBK, UL, BARD (Mini PBO Network, USGS Low Frequency Network, and Bay Area Regional Deformation Network)
Vault/Borehole ConditionsThe 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.
Plots & Figures
Installation of strainmeter at OHLN
Courtesy of the USGS
Completed OHLN site, with GPS monument
- Time series processing at the BSL
Last year Clean Clean & detrended Raw Raw & detrended Lifetime Clean Clean & detrended Raw Raw & detrended Text file (final results only) Clean Raw
GPS Station Pictures
Table of Seismic Instrumentation
Sensor Datalogger SEED Channels Location Geophone Mark Products L-22 Horizontal Geophone Q330-GFE EP?,LP?,SP? 40 Mark Products L-22 Vertical Geophone Q330-GFE EP?,LP?,SP? 40 Receiver Antenna Radome - GPS Topcon Net-G3A Ashtech Choke-Ring SCIGN Tall - Sensor Datalogger SEED Channels Location Others Paroscientific 8WD Digital Pressure Meter Q330-GFE LD? 40 Sacks 3-component Tensor Strainmeter Q330-GFE BS?,HS?,LS? 40 Pinnacle5000 QEP BA?,LA? EP Auxiliary VCOValue Q330-GFE AntennaCurrent Q330-GFE VK? 40 ClockPhase Q330-GFE VE? 40 ClockQuality Q330-GFE VE? 40 SystemCurrent Q330-GFE VC? 40 InputVoltage QEP LK? EP InternalHumidity QEP LI? EP InternalPressure QEP LD? EP InternalTemperature QEP LK? EP PLLOffset QEP LC? EP Setra Systems Model 270 Barometer QEP LD? EP SystemTemperature QEP LK? EP
Data & Metadata
Waveforms and associated metadata, and GPS data, are available at the Northern California Earthquake Data Center (NCEDC).
- BK Information Directory, including
Data completeness is defined both as "Completeness of observations" and "Cycle slips per observation". "Completeness of Obs." is the number of epochs in the final RINEX file normalized to the expected number. This percentage will go down if time is missing from the RINEX file. "Cycle slips per Obs." is the total number of detected cycle slip normalized to the total number of observations in the RINEX file. This number will increase as the receiver loses lock on satellites more frequently.
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The effects of multipath on the data are estimated by parameters for L1 and L2 (MP1 and MP2 respectively); see Estey and Meertens (GPS Solutions, 1999) for derivation. The daily value is the RMS of MP1 and MP2 throughout the day and for all satellites. Higher values indicate a greater prevalence and/or strength of multipathing, i.e. objects on the ground are providing multiple reflection pathways from the satellite to antenna.
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