MHDL - Marin Headlands, GG Nat'l Rec. Area, 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||MHDL (MHDL)|
|In Operation||2006/05/17 23:00:00 - Present|
LocationMHDL is located in the Marin Headlands of the Golden Gate National Recreation Area and was installed under the auspices of the National Park Service. This site is known as SFMAR in the USGS Low Frequency Network.
Although the installation is not complete as far as the data acquisition using the Quanterra datalogger, the USGS satellite system is installed and operational.
NetworkMini Plate Boundary Observatory Network (BK)
Bay Area Regional Deformation Network Network (BARD)
Franciscan Complex, Cretaceous and Jurassic sandstone
Borehole ConditionsThe MiniPBO borehole was installed on 08/06/2002. The strainmeter was installed at 520.6 ft and the seismometer package at 489.2 ft depth. This figure shows the location of equipment in the borehole.
GPS Monument DescriptionThreaded 5/8" rod cemented into concrete vault, in turn cemented onto bedrock
Seismic Station Pictures
View from the Marin Headlands
Installation of strainmeter at MHDL
- 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
|Geophone||Mark Products L-22 Horizontal Geophone||Q330-GFE||EP?,LP?,SP?||40|
|Mark Products L-22 Vertical Geophone||Q330-GFE||EP?,LP?,SP?||40|
|ElectroMagnetics Inc. BF4 Magnetometer||Q330||BT?,LT?,VT?||20|
|Paroscientific 8WD Digital Pressure Meter||Q330-GFE||LD?||40|
|Sacks 3-component Tensor Strainmeter||Q330-GFE||BS?,HS?,LS?||40|
|Setra Systems Model 270 Barometer||QEP||LD?||EP|
|GPS||SEPT POLARX5||Ashtech Choke-Ring||SCIGN Short||-|
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.
The Signal-to-Noise ratios are the mean values above the QC elevation mask for L1 and L2 respectively.