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OHLN - Ohlone Park, Hercules, CA, USA

Station Name OHLN (OHLN)
In Operation 2001/10/05 00:00:00 - Present
Latitude
Longitude:
Elevation: -0.50 meters
Instrumentation Borehole
GPS
Other


  • Site

    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.

    Network

    BK, UL, BARD (Mini PBO Network, USGS Low Frequency Network, and Bay Area Regional Deformation Network)

    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.

    GPS Monument Description

    1.25" pipe bolted into borehole casing
  • Plots & Figures

    Seismic Station Pictures

    Installation of strainmeter at OHLN<br>Courtesy of the USGS

    Installation of strainmeter at OHLN
    Courtesy of the USGS

    Completed OHLN site, with GPS monument

    Completed OHLN site, with GPS monument

    GPS Station Timeseries

    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

    OHLN

    OHLN

    OHLN

    OHLN

  • Instrumentation

    Table of Seismic Instrumentation

    SensorDataloggerSEED ChannelsLocation
    GeophoneMark Products L-22 Horizontal GeophoneQ330-GFEEP?,LP?,SP?40
    Mark Products L-22 Vertical GeophoneQ330-GFEEP?,LP?,SP?40
    ReceiverAntennaRadome-
    GPSTopcon Net-G3AAshtech Choke-RingSCIGN Tall-
    SensorDataloggerSEED ChannelsLocation
    OthersParoscientific 8WD Digital Pressure MeterQ330-GFELD?40
    Sacks 3-component Tensor StrainmeterQ330-GFEBS?,HS?,LS?40
    Pinnacle5000QEPBA?,LA?EP
    AuxiliaryVCOValueQ330-GFE
    AntennaCurrentQ330-GFEVK?40
    ClockPhaseQ330-GFEVE?40
    ClockQualityQ330-GFEVE?40
    SystemCurrentQ330-GFEVC?40
    InputVoltageQEPLK?EP
    InternalHumidityQEPLI?EP
    InternalPressureQEPLD?EP
    InternalTemperatureQEPLK?EP
    PLLOffsetQEPLC?EP
    Setra Systems Model 270 BarometerQEPLD?EP
    SystemTemperatureQEPLK?EP
  • Data & Metadata

    Waveforms and associated metadata, and GPS data, are available at the Northern California Earthquake Data Center (NCEDC).

    Waveform Data



    GPS Data

  • Data Quality

    Noise Analysis

    View more noise plots

    GPS Data Quality


    Completeness

    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.

    Previous Year
    OHLN completeness last year
    Lifetime
    OHLN completeness lifetime

    Multipath

    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.

    Previous Year
    OHLN multipath last year
    Lifetime
    OHLN multipath lifetime