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Northern Hayward Fault Network (NHFN)

Network | Equipment | Channels | SOH
Station Information | Data access | Reports | Collaborations

The Northern Hayward Fault Network (NHFN) is one of several networks of seismic instrumentation in northern and central California operated by the Berkeley Seismological Laboratory. Operations are partially supported by the USGS and by Caltrans. The NHFN is an array of borehole instrumentation deployed in the San Francisco Bay Area, with the goal of monitoring microseismicity on the Hayward fault. Data from these stations are transmitted to UC Berkeley using continuous telemetry and are analyzed for earthquakes. 7 sites are currently operational and additional stations are planned.

Network Code
BK (also includes the BDSN, MPBO, and MOBB)

Typical Station Equipment
3-component Oyo 4.5 Hz geophones
3-component Wilcoxon accelerometers
24-bit Quanterra digital data logger
GPS clock
Continuous telemetry to UC Berkeley
160 hour backup power supply

Typical Recorded Channels
Sensor SEED Channels Rate (samples/sec) Sampling Mode FIR Filter
Geophone EP1, EP2, EP3 100.0 Triggered Causal
Geophone DP1, DP2, DP3? 500.0 Triggered Causal
Accelerometer LL1, LL2, LL3 1.0 Continuous Acausal
Accelerometer BL1, BL2, BL3 20.0 Continuous Acausal
Accelerometer HL1, HL2, HL3 100.0 Continuous Causal
Accelerometer CL1, CL2, CL3 500.0 Triggered Causal

Normally, only 3 channels of acceleration and the vertical component geophone are recorded and archived. In some cases, sensor failure has led to different recording combinations.

Network State of Health
State of health is monitored through automated REDI alarm system notifications, waveform evaluations of significant and repeating small earthquakes and using SeisNetWatch software.

Station and Channel Information

Data access
Waveform data from the BK network are available in SEED format at the Northern California Earthquake Data Center. Several tools provide access to SEED format data at the NCEDC, both in terms of querying the archives and allowing data requests.

Help on using these tools is available.

Reports and Publications

The NHFN has been developed by the Berkeley Seismological Laboratory in collaboration with: