GASB - Alder Springs, CA, USA

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 GASB (GASB)
In Operation 2005/09/22 00:00:00 - Present
Elevation: 1354.8 meters
Instrumentation Broadband


The site is located at Alder Springs, CA, USA.

In addition to the UC Berkeley broadband and strong-motion sensor, this area is home to a short-period sensor operated by the California Department of Water Resources.

Support for GASB was provided by National Tsunami Hazard Program and the Governor's Office of Emergency Services as part of the California Integrated Seismic Network.


Berkeley Digital Seismic Network (BK)
Bay Area Regional Deformation Network Network (BARD)


Franciscan Complex Cretaceous and Jurassic sandstone

Borehole Conditions

The instruments are located in a steel and concrete vault benched into a gentle hillside and covered with soil overburden. The concrete pier is covered with 4" of insulation on the sides and 8" of insulation on the top. The datalogger and supporting equipment are in an adjacent room.

GPS Monument Description

Post fixed into the concrete that surrounds seismic vault. Post is reinforced by a concrete cylinder and three welded legs. The ends of the three legs were driven into the ground and filled in with cement.

Seismic Station Pictures

Construction at GASB

Construction at GASB

GASB vault under construction

GASB vault under construction

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

Table of Seismic Instrumentation

SensorDataloggerSEED ChannelsLocation
BroadbandStreckeisen STS-2 VBB Tri-Axial SeismometerQ330HR-GFEBH?,HH?,LH?,VH?00
AccelerometerKinemetrics FBA ES-T Accel. (4 g max 5 v/g)Q330HR-GFEHN?00
SensorDataloggerSEED ChannelsLocation

GPS Instrumentation

GPS-Topcon Choke-RingSCIGN Tall-

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


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
GASB completeness last year
GASB completeness lifetime


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
GASB multipath last year
GASB 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
GASB SNR last year
GASB SNR lifetime