Creepmeter

The data listed below are measures of surface fault slip (scaled in mm) as measured by creepmeters. Creepmeters consist of two piers separated by about 30 meters and connected by an invar wire. The main fault trace lies between the two piers. The invar wire oriented roughly a 30 degree angle from the local trace of the fault. A displacement transducer (LVDT) measures the change in length of the wire (or the change in distance between the piers).

For many of the creepmeters, the measurements are made once every 10 minutes and are sent via satellite telemetry to Menlo Park for analysis. In addition, periodic measurements are made manually for comparison with the electronically recorded data. For other creepmeters without telemetry, the measurements are made manually.

Below is a list of creepmeters, from North to South, located on the San Andreas, Hayward, and Calaveras Faults. For each site, the available data are listed. For sites with telemetry, the data are uploaded to this webpage daily. However, for the most recent observations, that is, within the past 2 weeks, they have not always been reviewed and, if needed, edited.

Note that at some sites, there exists both 10 minute and 1-day sampled data. The 10-minute and 1-day sampled data often do not cover the same interval of time. The 1-day data files will include older data.

The format of these data are year, day-of-year, and slip in mm. If there is a fourth column, then ignore that column.

How to Cite Creepmeter Data

Please reference Open-File Report 2024-1011, “Summary of Creepmeter Data from 1980 to 2020—Measurements Spanning the Hayward, Calaveras, and San Andreas Faults in Northern and Central California”

NameCodeLatitudeLongitudeInitial obs.NotesManual data10-minute sampling1-day sampling

Calaveras Fault

Shore Rd #1XSH136.9430-121.44501971
Shore Rd #2SHR236.9430-121.4450Apr-86
Hollister CentralHLC136.8570-121.4050Apr-70
Hollister D StHLD136.8420-121.4030Apr-70

Hayward Fault

Pt PinoleCPP137.9900-122.3560Aug. 1995
TemescalCTM137.8440-122.2270Mar. 1997
Oakland ZooCOZ137.7530-122.1500Nov. 1996
Hayward, Rose St #1HWR137.6800-122.0920Apr-68
Hayward, Rose St #2HWR237.6800-122.0920Apr-68
Hayward, D St #1HWE137.6700-122.0800Apr-68
Hayward, D St #2HWW137.6700-122.0800Apr-68
Hayward, Palisades St #1 HWP137.6630-122.0740Apr-68
Hayward, Palisades St #2CHP137.6630-122.0740Apr-94
Fremont WineryCFW137.5320-121.9520Dec. 1993

San Andreas Fault

San Juan Bautista; NylandSJN136.85460.00002004
San Juan Bautista #2XSJ236.8360-121.5210Jun-69
San Juan Bautista #3XSJ336.8360-121.5210Jan. 2007
Harris Ranch #1XHR136.7720-121.42201970
Harris Ranch #2XHR236.7720-121.4220Apr-85
Harris Ranch #3XHR336.7720-121.4220Aug. 2009
Cienega Winery CentralCWC336.7500-121.3850Nov. 1968
Cienega Winery NorthCWN136.7500-121.3850Jun-72
Frank Lewis LongXFL136.6650-121.2720Apr-73
Melendy RanchXMR136.5950-121.1870Jun-69
Melendy WindmillMRW136.5850-121.1770Sept. 1972
Dry Lake LongXDL236.4920-121.07801978
BitterwaterBIT136.3980-120.9820Jul-79
Monarch Peak #1XMP136.2170-120.7980Jun-69
Monarch Peak #1XMP236.2170-120.7980Jun-69
Slacks CanyonXSC136.0650-120.6280Jun-79
Middle MtnXMM135.9580-120.5020Oct. 1979
Middle Mtn; Big CreepXMBC35.9580-120.5020Apr-04
Middle RidgeXMD135.9430-120.4850Jul-86
VarianXVA135.9220-120.4620Apr-87
Roberson, SW traceXRSW35.9070-120.4600May-87
Parkfield, #1XPK135.9020-120.4420Oct. 1979
Parkfield, #2XPK235.9020-120.4420Sept. 2004
Taylor RanchXTA135.8900-120.4270Sept. 1985
Taylor Ranch; Big CreepTABC35.8900-120.4270Mar-04
Hearst, SW traceXHSW35.8620-120.4200Jun-87
Work RanchWKR135.8580-120.39201976
Carr RanchCRR135.8350-120.3630May-66
Gold HillXGH135.8200-120.3480Jul-69
Highway 46C46135.7240-120.2820Sept. 2004
Highway 46X46135.7230-120.2780Aug. 1986
Twisselman RanchTWR135.5970-120.1470Nov. 1976
Panorama HillsXPH135.1480-119.6920Aug. 1977

Dilatometer

The data listed below are measures of changes in volumetric strain (units of 0.001 part per million) as a function of time for instruments in California. Outliers due to telemetry problems, instrument visits, and etc have been removed. Offsets due to valve resets have been removed. Data are provided in two modes; 1) Cleaned strain data and 2) Clean strain data adjusted for the Earth Tide and atmospheric pressure changes. Pressure data (not scaled to units of pressure) are also provided.

The format of these data are year, day-of-year, and slip in mm. If there is a fourth column, then ignore that column.

Data are complete through the end of 2019. More data exist, but have not been archived.

The ReadMe file contains the lists of offsets and data removed for analysis. In addition, there is a table listing the estimates of the amplitude and phase of the O1 and M2 tides calculated as a function of time for the strainmeter.

NameCodeLatitudeLongitudeInitial obs.NotesDilatation cleanDilitation adjustedPressure data

Long Valley

Big SpringsBG37.7610-118.9440Jul. 2007
PostpilePO37.6350-119.0830Jul. 2007
MotocrossMX37.6160-118.9520Jul. 2007

Parkfield

Donna LeaDL35.9400-120.4240Jan. 2008
Vineyard CanyonVC35.9220-120.5350Jan. 2008
FrolichFR35.9110-120.4870Jan. 2008
Jack CanyonJC35.7150-120.2060Dec. 2007
Red HillsRH35.6240-120.2570May-08

San Francisco Bay Area

Russel RanchRR37.9200-122.1500Sept. 2006
GarinGA37.6500-122.0100Sept. 2006
SunolSU37.6400-121.9400Aug. 2006
CoyoteCY37.5630-122.0970Sept. 2006
Mill CreekMC37.5500-121.9000Jul-06

Southern Californa

Chantry FlatCN34.1960-118.0230Feb. 2007
Big DaltonBD34.1680-117.8140Feb. 2007

Tensor Strainmeter

The data listed below are measures of changes in tensor strain (units of 0.001 part per million) as a function of time for instruments in California. We are providing data for two different instruments, one is a three component strainmeter made by Carnegie Dept. of Terrestial Magnetism (DTM) and the other is a three or 4 component strainmeter made by GTSM Technologies. Since these instruments have at least 3 extensometers, these data can be combined into tensor strain based upon analysis using the Earth Tides. We provide both the extensometer and the tensor strain changes. Data are provided in two modes; 1) Cleaned strain data and 2) Clean strain data adjusted for the Earth Tide and atmospheric pressure changes. Outliers due to telemetry problems, instrument visits, and etc have been removed. Offsets due to valve resets, for the Carnegie, DTM instruments, have been removed. Pressure data (not scaled to units of pressure) are also provided. Gauge data for the DTM instruments are not scaled to physical units.

For the GTSM instruments, the data are complete. These GTSM instruments are identified with a 3 letter code. None of these GTSM instruments currently work after more than 20 years of continuous operation.

For the DTM instruments, the data are complete through the end of 2019. More data exist, but have not been archived.

The ReadMe file contains the lists of offsets and data removed for analysis. In addition, there is a table listing the estimates of the amplitude and phase of the O1 and M2 tides calculated as a function of time for the strainmeter.

The format of these data are year, day-of-year, and slip in mm. If there is a fourth column, then ignore that column.

NameCodeLatitudeLongitudeInitial obs.Instrument typeNotesPressure dataGage data cleanGage data adjustedTensor data cleanTensor data adjusted

Parkfield

Donna LeaDLT35.9400-120.4250Jan. 1988
Frolich (2)FLT35.9100-120.4900Mar. 1988
Eades (3)EDT35.8900-120.4200Jan. 1988

San Francisco Bay Area

Saint VincentsSV38.0330-122.5260Jan. 2008
OhloneOH38.0070-122.2740Jan. 2008
Marin HeadlandsMH37.8420-122.4940May-08
ChabotCHT37.7430-122.0970Jun. 1993
BrisbaneBB37.6870-122.4100Apr. 2008
Garin (1)GAT37.6500-122.0100Jan. 1993
Ox MountainOX37.4980-122.4250Jan. 2008
San Juan BautistaSJT36.8370-121.5440Jan. 1984

Southern California

ColdbrokCBT34.2900-117.8400Jan-97
Pinon Flat (4)PFT33.6200-116.4500Jan-83
  1. Ceased working in Sep 1998
  2. Ceased working; second gage in Dec 2005
  3. Ceased working in Apr 2002
  4. Ceased working in Dec 2002