Overview of the Hayward Fault Network

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

Map of NHFN stations
Table of NHFN stations
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
Information on Quanterra Timing Errors

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.

Querying the archives
- SeismiQuery at the NCEDC
- NetDC Request Form
Requesting data by channel and time
- NetDC Request Form
Requesting data by event
- EVT_FAST request for NC data

Help on using these tools is available.

Reports and Publications

Reports on the NHFN from the Annual Report of the BSL:

Collaborations

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