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 |
| Latitude | |
| Longitude: | |
| Elevation: | 1354.8 meters |
| Instrumentation | Broadband GPS |
Location
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.
Network
Berkeley Digital Seismic Network (BK)Bay Area Regional Deformation Network Network (BARD)
Geology
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 |
GASB vault under construction |
GPS Station Timeseries
- Time series processing at the BSL *
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Last year Clean Clean & detrended Raw Raw & detrended Lifetime Clean Clean & detrended Raw Raw & detrended Text file (final results only) Clean Raw
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*discontinued
GPS Station Pictures
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Table of Seismic Instrumentation
| Sensor | Datalogger | SEED Channels | Location | |
| Broadband | Streckeisen STS-2 VBB Tri-Axial Seismometer | Q330HR-GFE | BH?,HH?,LH?,VH? | 00 |
| Accelerometer | Kinemetrics FBA ES-T Accel. (4 g max 5 v/g) | Q330HR-GFE | HN? | 00 |
| Sensor | Datalogger | SEED Channels | Location | |
| Auxiliary | AntennaCurrent | Q330HR-GFE | VE? | 00 |
| ClockPhase | Q330HR-GFE | LC?,VC? | 00 | |
| ClockQuality | Q330HR-GFE | LC?,VC? | 00 | |
| InputVoltage | Q330HR-GFE | VE? | 00 | |
| SystemCurrent | Q330HR-GFE | VE? | 00 | |
| SystemTemperature | Q330HR-GFE | VK? | 00 | |
| VCOValue | Q330HR-GFE | VC? | 00 |
GPS Instrumentation
| Receiver | Antenna | Radome | - | |
| GPS | - | Topcon Choke-Ring | SCIGN Tall | - |
Waveforms and associated metadata, and GPS data, are available at the Northern California Earthquake Data Center (NCEDC).
Waveform Data
- BK Information Directory, including
- List of station locations
- List of available channels
- Instrument Response
- Querying the archives
- Download waveform data
GPS Data
- Site log: gasb.log
Data Type From To Low-rate raw --- --- Low-rate rinex 6/17/2011 present High-rate raw 6/17/2011 present High-rate rinex 6/17/2011 present
Noise Analysis
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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.
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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.
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Signal-to-Noise Ratio
The Signal-to-Noise ratios are the mean values above the QC elevation mask for L1 and L2 respectively.
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