SAO - San Andreas Geophysical Obs., Hollister, 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||SAO (SAOB)|
|In Operation||1988/01/28 00:00:00 - Present|
LocationSite is located at the San Andreas Geophysical Observatory in the Hollister Hills State Vehicle Recreation Area. The BSL first occupied this site in 1966, with a variety of geophysical instrumentation. The digital broadband sensors were installed in 1988.
SAO is a cooperative station with the Advanced National Seismic System.
NetworkBerkeley Digital Seismic Network (BK)
Bay Area Regional Deformation Network Network (BARD)
Jurassic-Cretaceous Gabilan Granite
Borehole ConditionsThe vault is a buried steel culvert liner with a set of three isolation doors leading to the interior. The pier is poured concrete. The datalogger and supporting equipment are located in an air-conditioned structure approximately 50' away and connected via underground conduits. The seismometers are thermally insulated with 4" of polyurethane foam.
GPS Monument DescriptionReinforced concrete monument
Seismic Station Pictures
View of SAO equipment building
View of SAO vault
- 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
|Broadband||Streckeisen STS-1/E300 VBB Feedback Seismometer||Q330HR-GFE||BH?,HH?,LH?,VH?||00|
|Accelerometer||Kinemetrics FBA ES-T Accel. GFE (4 g max 5 v/g)||Q330HR-GFE||HN?||00|
|GPS||Trimble NetRS||Ashtech Choke-Ring||SCIGN Tall||-|
|Others||Electric Field Dipole (Pb-PbCl or Cu-CuS Anodes)||Q4120||BQ?,LQ?,UQ?,VQ?|
|ElectroMagnetics Inc. BF4 Magnetometer||Q4120||BT?,LT?,UT?,VT?|
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.
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.