CMB - Columbia College

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

Load California Faults

Station Name	CMB (CMBB)
In Operation	1986/10/25 00:00:00 - Present
Latitude
Longitude:
Elevation:	695.7233 meters
Instrumentation	Broadband GPS

Site

Location

Site is located on the campus of Columbia College in Sonora, California. This site was established to relocate instrumentation from the JAS1 in Jamestown.

CMB was upgraded with partial funding from the IRIS Consortium and data are archived at the IRIS Data Management Center as well as the NCEDC. CMB is also a cooperative station with the Advanced National Seismic System.

Network

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

Geology

Paleozoic marine limestone

Borehole Conditions

The vault is a buried fiberglass cylinder, eight feet in diameter and six feet deep. It has a flat top at grade level with a hatch for entry. The floor is concrete poured directly on rock. The datalogger and supporting equipment are located in an air conditioned trailer located about 70 feet from the vault and connected via underground conduits. The seismometers are thermally insulated with 4" of polyurethane foam and the top of the vault is covered with bark for additional insulation.

GPS Monument Description

Poured concrete cylinder with steel reinforcement

Plots & Figures

Seismic Station Pictures

Site of CMB vault

STS-7 enclosure at CMB

GPS Station Daily Timeseries

GPS Station Pictures

CMBB

Instrumentation

Table of Seismic Instrumentation

	Sensor	Datalogger	SEED Channels	Location
Broadband	STS-7	Q330HR	BH?,HH?,LH?,VH?	00
Accelerometer	EPISENSOR ES-T	Q330HR	HN?	00
Auxiliary	ANTENNACURRENT	Q330HR	VE?	00
	CLOCKPHASE	Q330HR	LC?,VC?	00
	CLOCKQUALITY	Q330HR	LC?,VC?	00
	SYSTEMCURRENT	Q330HR	VE?	00
	VCOVALUE	Q330HR	VC?	00
	CALIBRATIONINPUT	Q330HR	LC?	EP
	INPUTVOLTAGE	Q330HR	LE?	EP
	MODEL 270	Q330HR	LD?	EP
	SYSTEMHUMIDITY	Q330HR	LI?	EP
	SYSTEMPRESSURE	Q330HR	LD?	EP
	SYSTEMTEMPERATURE	Q330HR	LK?	EP

GPS Instrumentation

	Receiver	Antenna	Radome	-
GPS	SEPTENTRIO POLARX5	SEPTENTRIO SEPCHOKE_B3E6	SPKE	-

Data & Metadata

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
  - Year/month/day format
  - Year,doy format
- Instrument Response
  - SEED format
  - Simplified Responses

Querying the archives
- SeismiQuery at the NCEDC
Download waveform data

GPS Data

Site log: cmbb.log

Data Type From To

Low-rate raw 12/09/1993 11/5/2005

Low-rate rinex 12/09/1993 present

High-rate raw 11/5/2005 present

High-rate rinex 5/1/2010 present

Data Type	From	To
Low-rate raw	12/09/1993	11/5/2005
Low-rate rinex	12/09/1993	present
High-rate raw	11/5/2005	present
High-rate rinex	5/1/2010	present

Data Quality

Noise Analysis

View more noise plots

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.

Previous Year

Lifetime

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.

Previous Year

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

Lifetime