BRIB - Briones Reservoir

We operate broadband and borehole stations under the network code BK. The Berkeley Digital Seismic Network (BDSN) is a regional network of very broadband and strong motion seismic stations designed to monitor regional seismic activity as well as provide high quality data. The Berkeley borehole stations have borehole geophones or other seismic sensors and may have other geophysical instrumentation.

BARD is our GPS network for monitoring crustal deformation across the Pacific-North America plate boundary and in the San Francisco Bay Area for earthquake hazard reduction studies and rapid earthquake emergency response assessment



Station Name BRIB (BRI2)
In Operation 1995/06/23 16:00:00 - Present
Latitude
Longitude:
Elevation: 265.1227 meters
Instrumentation Broadband
Borehole
GPS
Other

Location

Site is located at the Russell Reservation Field Station of UC Berkeley's College of Natural Resources, adjacent to Briones Regional Park in Orinda, California. This is a collaborative site with instrumentation for the BDSN, HFN, BARD, and the USGS strainmeter networks. This site is known as SFRRL in the USGS network.

Network

Berkeley Digital Seismic Network (BK)
Northern Hayward Fault Network (BK)
Mini Plate Boundary Observatory Network (BK)
Bay Area Regional Deformation Network Network (BARD)
USGS Low Frequency Network (UL)

Geology

Sandstone

Borehole Conditions

The BRIB site experienced catastrophic flooding in December 2016, destroying the instrumentation and vault. There is not data available/recorded from 2014/12/16 03:00:00 to 2019/09/17 01:20:00. The station was moved to a different area at the same location on 2019/09/17 and re-instrumented.

In early 2019 it was discovered that the BRIB GPS monument at BRIB was very wobbly and the cable conduit from the monument was damaged. Deigo Melgar also reported excess noise levels (see attached displacement and PPSD plots). Data were archived up to 2019/03/19, and then data acquisition and monitoring were turned off until the monument could be structurally restored or completely replaced. Engineers installed a new GNSS site BRI2 on 2019/12/09.


About previous instrumentation:

The instruments are sited in a borehole located on the Russell Reservation. Geophysical instruments are installed at three levels in the 108-meter deep hole. A dilatometer strainmeter, part of the USGS strainmeter network, is installed at the depth of 162 meters. Above the strainmeters, the 6-component HFN package is installed at a depth of 119 meters. The Guralp CMG-3T seismometer of the BDSN is installed at a depth of 35 meters. The FBA-23 is installed at the surface of the borehole. The BARD GPS receiver is located up the hill.

On 11/19/1996, the Seismological Laboratory installed a second CMG-3T in a small tank at the surface. Data recording of this sensor replaced the borehole instrument. This site experienced frequent tilts, primarily due to changes in ground water content. In the fall of 2000, BSL engineers installed a post-hole and relocated the Guralp CMG-3T from the borehole to this site. Recording of the post-hole installation began on 12/20/2000. The Guralp in the surface tank has been removed.

GPS Monument Description

Shallow-drilled braced monument in sedimentary bedrock.

Seismic Station Pictures

Looking east

Looking east

Looking south

Looking south

GPS Station Timeseries

GPS Station Pictures

Looking north

Looking north

Looking west

Looking west

Table of Seismic Instrumentation

SensorDataloggerSEED ChannelsLocation
BroadbandMBB-2Q8BH?,HH?,LH?01
AccelerometerEPISENSOR ES-TQ8HN?,LN?01

GPS Instrumentation

ReceiverAntennaRadome-
GPSSEPTENTRIO POLARX5SEPTENTRIO SEPCHOKE_B3E6SPKE-

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

Waveform Data



GPS Data

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
BRI2 completeness last year
Lifetime
BRI2 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
BRI2 multipath last year
Lifetime
BRI2 multipath lifetime

Signal-to-Noise Ratio

The Signal-to-Noise ratios are the mean values above the QC elevation mask for L1 and L2 respectively.

Previous Year
BRI2 SNR last year
Lifetime
BRI2 SNR lifetime