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
24-bit GERI multi-channel data acquisition system.
GPS clock
On-site recording.
Current Equipment
| Sensor Site | Lat. | Lon. | Elev. | Start Date | End Date | Instrumentation | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| MH025 | 35.9742 | -120.5521 | 660.50 | 2012/01/12 00:00:00 | Present |
|
Previous Equipment
| Sensor Site | Lat. | Lon. | Elev. | Start Date | End 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
24-bit GERI multi-channel data acquisition system.
GPS clock
On-site recording.
Previous Equipment
| Sensor Site | Lat. | Lon. | Elev. | Start Date | End 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
- SF Information Directory, including
- List of station locations
- List of available channels
- Instrument Response
Data access
The SAFOD pilot hole trigger list provides a list of NCEDC triggerids and trigger times. 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
- Access data through NCEDC web services
Help on using these tools is available.
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
- Access data through NCEDC web services
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
SAFOD is one component of the EarthScope Major Research Initiative funded by the National Science Foundations (NSF).
