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SAFOD (San Andreas Fault Observatory at Depth)

The San Andreas Fault Observatory at Depth (SAFOD) is a deep borehole observatory that will directly measure the physical conditions under which plate boundary earthquakes occur. SAFOD is one component of the EarthScope Major Research Initiative funded by the National Science Foundations (NSF). The SAFOD site is located in the Parkfield region of northern California.

Data from SAFOD has been assigned a network code of SF.

Click on each topic below to expand to more information.

Network Overview and History

The SAFOD main hole is a 3.2 km inclined borehole across the San Andreas Fault Zone. The SAFOD pilot hole is a separate, 2.2-km-deep scientific drilling experiment at the same surface location as SAFOD. This site is ~ 1.8 km SW of the San Andreas fault near Parkfield, CA, on a segment of the fault that moves through a combination of aseismic creep and repeating microearthquakes. It lies just north of the rupture zone of the 2004, magnitude 6 Parkfield earthquake, the most recent in a series of events that have ruptured the fault six times since 1857. The Parkfield region is the most comprehensively instrumented section of a fault anywhere in the world, and has been the focus of intensive study for the past two decades as part of the Parkfield Earthquake Experiment. The SAFOD hole are a collaborative effort between the International Continental Drilling Program (ICDP), the NSF through its EarthScope program, and the U.S. Geological Survey (USGS).

The SAFOD pilot hole was initially instrumented with a seismic string containing 32 levels of 3-component 15-Hz geophones. The sensors were recorded by a GERI 24-bit mutichannel recorder. The event waveform data from 2002/09/13 through 2004/05/30 contain all 96 channels of data.

In the process of drilling the main SAFOD hole in 2004, the pilot hole sensor string was inadvertently damaged, resulting in a loss of the lower 25 sensor packages. The waveforms from 2004/09/26 through 2004/10/30 therefore contain waveforms only from the remaining 7 sensors (21 channels). This sensor string was later remove, and a single 3-component seismometer has been deployed in summer 2005 and most of 2006. Continuous recordings from 2006/01/17 through 2006/11/19 consists of 6 data channels at 2 distinct depths in the main hole, and 3 data channels at one depth in the pilot hole. Since 2006, a variety of equipment has been in the Pilot Hole, including a package with a broadband seismometer, accelerometer and downhole digitizer between 2008/03/06 and 2009/05/27. There is currently no instrumentation operating in the Pilot Hole. Since 2008/12/01 the Main Hole has been populated by a series of three-component geophones recorded on Reftek 130 data loggers.

Main Hole Equipment

Original Equipment
2 levels of 3-component GS-20DM 15 Hz geophone sensors
24-bit GERI multi-channel data acquisition system.
GPS clock
On-site recording.

Current Equipment

Sensor SiteLat.Lon.Elev.Start DateEnd Date Instrumentation
MH02535.9742-120.5521660.502012/01/12 00:00:00Present
SensorDatalogger
GS-20DMReftek-130
SEED ChannelsLocation
GP?01

Previous Equipment
Sensor SiteLat.Lon.Elev.Start DateEnd Date Previous Instr.
MH001 35.9742 -120.5521 627.30 2004/11/13 17:31:00 2004/11/14 00:55:00 Previous instr.
MH002 35.9742 -120.5521 627.30 2004/11/14 17:18:00 2004/11/14 19:44:00 Previous instr.
MH003 35.9742 -120.5521 627.30 2004/12/16 23:35:00 2005/02/09 11:27:00 Previous instr.
MH007 35.9742 -120.5521 627.30 2006/01/17 22:13:00 2006/01/19 20:27:00 Previous instr.
MH008 35.9742 -120.5521 627.30 2006/02/04 04:27:00 2006/02/16 12:12:00 Previous instr.
MH009 35.9742 -120.5521 627.30 2006/04/28 20:40:00 2006/05/14 01:32:00 Previous instr.
MH010 35.9742 -120.5521 627.30 2006/07/12 01:23:00 2006/07/16 10:56:00 Previous instr.
MH011 35.9742 -120.5521 627.30 2006/08/02 21:45:00 2006/09/14 14:10:00 Previous instr.
MH012 35.9742 -120.5521 627.30 2006/10/25 00:14:00 2006/10/26 16:08:00 Previous instr.
MH013 35.9742 -120.5521 627.30 2006/10/26 19:10:00 2006/10/30 21:20:00 Previous instr.
MH014 35.9742 -120.5521 627.30 2006/10/31 16:45:00 2006/11/01 23:10:00 Previous instr.
MH015 35.9742 -120.5521 627.30 2006/11/01 18:47:00 2006/11/02 15:51:00 Previous instr.
MH016 35.9742 -120.5521 627.30 2006/11/09 21:12:00 2006/11/16 15:56:00 Previous instr.
MH017 35.9742 -120.5521 627.30 2007/01/11 01:12:00 2007/01/18 17:42:00 Previous instr.
MH018 35.9742 -120.5521 627.30 2007/03/24 00:00:00 2007/03/27 00:00:00 Previous instr.
MH020 35.9742 -120.5521 660.50 2008/09/29 15:00:00 2008/10/14 23:59:59 Previous instr.
MH021 35.9742 -120.5521 660.50 2008/12/01 00:00:00 2009/05/05 20:59:00 Previous instr.
MH022 35.9742 -120.5521 660.50 2009/05/06 00:00:00 2010/09/20 23:59:59 Previous instr.
MH023 35.9742 -120.5521 660.50 2010/12/09 00:00:00 2011/12/15 20:24:00 Previous instr.
MH024 35.9742 -120.5521 660.50 2011/12/15 22:47:00 2012/01/11 21:07:00 Previous instr.


Pilot Hole Equipment

Original Equipment
32 levels of 3-component GS-20DM 15 Hz geophone sensors
24-bit GERI multi-channel data acquisition system.
GPS clock
On-site recording.


Previous Equipment

Sensor SiteLat.Lon.Elev.Start DateEnd Date Previous Instr.
PH001 35.9743 -120.5521 627.30 2002/09/13 11:21:00 2005/02/09 11:27:00 Previous instr.
PH002 35.9743 -120.5521 627.30 2005/05/04 21:41:00 2005/05/06 05:55:00 Previous instr.
PH003 35.9743 -120.5521 627.30 2005/05/21 22:45:00 2005/09/12 19:00:00 Previous instr.
PH004 35.9743 -120.5521 627.30 2006/01/17 22:13:00 2006/11/08 21:27:00 Previous instr.
PH005 35.9743 -120.5521 627.30 2007/03/24 00:00:00 2007/06/07 19:04:00 Previous instr.
PH006 35.9743 -120.5521 627.30 2007/06/06 21:10:35 2008/02/08 01:29:00 Previous instr.
PH007 35.9743 -120.5521 627.30 2008/02/08 01:30:41 2008/02/14 21:48:00 Previous instr.
PH008 35.9743 -120.5521 627.30 2008/03/06 18:00:00 2009/05/27 20:12:00 Previous instr.


Station Information

Data access

All SAFOD pilot hole and main hole seismic waveform data are available in SEED format. The triggered pilot data may be accessed using SEED-format tools as well as through the EVT_FAST waveform request form, which allows you to request waveform by trigger id.

The SAFOD pilot hole trigger list provides a list of NCEDC triggerids and trigger times that can be used with EVT_FAST or STP waveform request system. 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.

SAFOD tilt data are available as an "assembled data set" here.

The NCEDC also has event and continuous waveform data covering the same time periods from the Parkfield borehole High Resolution Seismic Network and the Northern California Seismic Network as well as the authoritative earthquake catalog for the region.



Collaborations

The waveform data from the SAFOD pilot hole from 2002/09/13 through 2004/12/31 was recorded by and provided to the NCEDC by the research group of Dr. Peter Malin at Duke University.

SAFOD is one component of the EarthScope Major Research Initiative funded by the National Science Foundations (NSF).