MHC - Lick Observatory, Mt. Hamiliton, 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 MHC (MHCB)
In Operation 1986/09/10 00:00:00 - Present
Elevation: 1250.4 meters
Instrumentation Broadband


Site is located at the Lick Observatory atop Mount Hamilton, and is under the auspices of UC Santa Cruz. The site was first established in 1887 with the installation of the first seismic sensors in North America, and has been occupied continuously since then. Wood-Anderson seismographs were deployed at this site in 1928 and operated until 1993. The first digital broadband instrumentation was deployed in 1987.


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


Jurassic-Cretaceous Franciscan greywacke and greenstone

Borehole Conditions

The vault is located in a room in the east wing of the Lick Observatory. The piers are reinforced concrete which are isolated from the building. The seismometer room is isolated from the hallway via two doors and the datalogger and supporting equipment are in an adjacent room. The seismometers are thermally insulated with 4" of polyurethane foam.

GPS Monument Description

Threaded 5/8" rod cemented into roof of concrete building.

Seismic Station Pictures

View of the dome at MHC

View of the dome at MHC

Typical STS-1 installation

Typical STS-1 installation

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-1 VBB Feedback Horizontal SeismometerQ330HR-GFEBH?,HH?,LH?,VH?00
Streckeisen STS-1 VBB Feedback Vertical SeismometerQ330HR-GFEBH?,HH?,LH?,VH?00
AccelerometerKinemetrics FBA ES-T Accel. (2 g max 10 v/g)Q330HR-GFEHN?00
SensorDataloggerSEED ChannelsLocation

GPS Instrumentation

GPSSeptentrio PolaRx5Ashtech Choke-RingSCIGN Short-

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
MHCB completeness last year
MHCB 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
MHCB multipath last year
MHCB 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
MHCB SNR last year
MHCB SNR lifetime