Creepmeter
The data listed below are measurements 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 or similar length standard. 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 the USGS office at Moffett Field 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 is year, day-of-year, and slip in mm. If there is a fourth column, then ignore that column.
FDuring the COVID pandemic, many of the sites have degraded due to lack of maintenance to the aged equipment. Several sites have had long gaps and lose of baseline data to bridge the gap. In those cases, the offset in time series is estimated by least squares regression assuming a constant rate; those estimates are just estimates and should be used with caution.
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”
| Name | Code | Latitude | Longitude | Initial obs. | Notes | Manual data | 10-minute sampling | 1-day sampling |
|---|---|---|---|---|---|---|---|---|
Calaveras Fault | ||||||||
| Shore Rd #1 | XSH1 | 36.9430 | -121.4450 | 1971 | | | | |
| Shore Rd #2 | SHR2 | 36.9430 | -121.4450 | Apr-86 | | | | |
| Hollister Central | HLC1 | 36.8570 | -121.4050 | Apr-70 | | | | |
| Hollister D St | HLD1 | 36.8420 | -121.4030 | Apr-70 | | | | |
Hayward Fault | ||||||||
| Pt Pinole | CPP1 | 37.9900 | -122.3560 | Aug. 1995 | | | | |
| Temescal | CTM1 | 37.8440 | -122.2270 | Mar. 1997 | | | | |
| Oakland Zoo | COZ1 | 37.7530 | -122.1500 | Nov. 1996 | | | | |
| Hayward, Rose St #1 | HWR1 | 37.6800 | -122.0920 | Apr-68 | | | | |
| Hayward, Rose St #2 | HWR2 | 37.6800 | -122.0920 | Apr-68 | | | | |
| Hayward, D St #1 | HWE1 | 37.6700 | -122.0800 | Apr-68 | | | | |
| Hayward, D St #2 | HWW1 | 37.6700 | -122.0800 | Apr-68 | | | | |
| Hayward, Palisades St #1 | HWP1 | 37.6630 | -122.0740 | Apr-68 | | | | |
| Hayward, Palisades St #2 | CHP1 | 37.6630 | -122.0740 | Apr-94 | | | | |
| Fremont Winery | CFW1 | 37.5320 | -121.9520 | Dec. 1993 | | | | |
San Andreas Fault | ||||||||
| San Juan Bautista; Nyland | SJN1 | 36.8546 | 0.0000 | 2004 | | | | |
| San Juan Bautista #2 | XSJ2 | 36.8360 | -121.5210 | Jun-69 | | | | |
| San Juan Bautista #3 | XSJ3 | 36.8360 | -121.5210 | Jan. 2007 | | | | |
| Harris Ranch #1 | XHR1 | 36.7720 | -121.4220 | 1970 | | | | |
| Harris Ranch #2 | XHR2 | 36.7720 | -121.4220 | Apr-85 | | | | |
| Harris Ranch #3 | XHR3 | 36.7720 | -121.4220 | Aug. 2009 | | | | |
| Cienega Winery Central | CWC3 | 36.7500 | -121.3850 | Nov. 1968 | | | | |
| Cienega Winery North | CWN1 | 36.7500 | -121.3850 | Jun-72 | | | | |
| Frank Lewis Long | XFL1 | 36.6650 | -121.2720 | Apr-73 | | | | |
| Melendy Ranch | XMR1 | 36.5950 | -121.1870 | Jun-69 | | | | |
| Melendy Windmill | MRW1 | 36.5850 | -121.1770 | Sept. 1972 | | | | |
| Dry Lake Long | XDL2 | 36.4920 | -121.0780 | 1978 | | | | |
| Bitterwater | BIT1 | 36.3980 | -120.9820 | Jul-79 | | | | |
| Monarch Peak #1 | XMP1 | 36.2170 | -120.7980 | Jun-69 | | | | |
| Monarch Peak #1 | XMP2 | 36.2170 | -120.7980 | Jun-69 | | | | |
| Slacks Canyon | XSC1 | 36.0650 | -120.6280 | Jun-79 | | | | |
| Middle Mtn | XMM1 | 35.9580 | -120.5020 | Oct. 1979 | | | | |
| Middle Mtn; Big Creep | XMBC | 35.9580 | -120.5020 | Apr-04 | | | | |
| Middle Ridge | XMD1 | 35.9430 | -120.4850 | Jul-86 | | | | |
| Varian | XVA1 | 35.9220 | -120.4620 | Apr-87 | | | | |
| Roberson, SW trace | XRSW | 35.9070 | -120.4600 | May-87 | | | | |
| Parkfield, #1 | XPK1 | 35.9020 | -120.4420 | Oct. 1979 | | | | |
| Parkfield, #2 | XPK2 | 35.9020 | -120.4420 | Sept. 2004 | | | | |
| Taylor Ranch | XTA1 | 35.8900 | -120.4270 | Sept. 1985 | | | | |
| Taylor Ranch; Big Creep | TABC | 35.8900 | -120.4270 | Mar-04 | | | | |
| Hearst, SW trace | XHSW | 35.8620 | -120.4200 | Jun-87 | | | | |
| Work Ranch | WKR1 | 35.8580 | -120.3920 | 1976 | | | | |
| Carr Ranch | CRR1 | 35.8350 | -120.3630 | May-66 | | | | |
| Gold Hill | XGH1 | 35.8200 | -120.3480 | Jul-69 | | | | |
| Highway 46 | C461 | 35.7240 | -120.2820 | Sept. 2004 | | | | |
| Highway 46 | X461 | 35.7230 | -120.2780 | Aug. 1986 | | | | |
| Twisselman Ranch | TWR1 | 35.5970 | -120.1470 | Nov. 1976 | | | | |
| Panorama Hills | XPH1 | 35.1480 | -119.6920 | Aug. 1977 | | | | |
Dilatometer
The data listed below are measurements 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, 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 is year, day-of-year, and slip in mm. If there is a fourth column, then ignore that column. The files in this archive typically consist of measurements at 10-minute intervals. For many of the dilatometers, especially those located in the SF Bay Area, high sample rate, 100 sps, data exist as miniSeed files from NCEDC.org website.
Data are complete through May 2025. More data exist but have not been archived. In this archive, the data extend back to the time when the telemetry was changed to a newer model of digitizer and transmitter which occurred in mid-2006 for sites in the SF Bay area, winter-2007 for southern California sites, and summer-2007 for Long Valley sites. Although the telemetry was also changed at the Parkfield sites, the data from this archive extend to 2003 to cover the times of both the San Simeon (Dec 2003) and Parkfield (Sept. 2004) earthquakes.
The ReadMe file contains the lists of offsets and data removed for analysis. In addition, there is a plot and table listing the estimates of the amplitude and phase of the O1 and M2 tides calculated as a function of time for the strainmeter. Abnormal variations of these parameters can be due to poor strainmeter data and/or incomplete editing of the strain (or atmospheric pressure) data.
| Name | Code | Latitude | Longitude | Initial obs. | Notes | Dilatation clean | Dilitation adjusted | Pressure data |
|---|---|---|---|---|---|---|---|---|
Long Valley | ||||||||
| Big Springs | BG | 37.7610 | -118.9440 | Jul. 2007 | | | | |
| Postpile | PO | 37.6350 | -119.0830 | Jul. 2007 | | | | |
| Motocross | MX | 37.6160 | -118.9520 | Jul. 2007 | | | | |
Parkfield | ||||||||
| Donna Lea | DL | 35.9400 | -120.4240 | Jan. 2008 | | | | |
| Vineyard Canyon | VC | 35.9220 | -120.5350 | Jan. 2008 | | | | |
| Frolich | FR | 35.9110 | -120.4870 | Jan. 2008 | | | | |
| Jack Canyon | JC | 35.7150 | -120.2060 | Dec. 2007 | | | | |
| Red Hills | RH | 35.6240 | -120.2570 | May-08 | | | | |
San Francisco Bay Area | ||||||||
| Russel Ranch | RR | 37.9200 | -122.1500 | Sept. 2006 | | | | |
| Garin | GA | 37.6500 | -122.0100 | Sept. 2006 | | | | |
| Sunol | SU | 37.6400 | -121.9400 | Aug. 2006 | | | | |
| Coyote | CY | 37.5630 | -122.0970 | Sept. 2006 | | | | |
| Mill Creek | MC | 37.5500 | -121.9000 | Jul-06 | | | | |
Southern Californa | ||||||||
| Chantry Flat | CN | 34.1960 | -118.0230 | Feb. 2007 | | | | |
| Big Dalton | BD | 34.1680 | -117.8140 | Feb. 2007 | | | | |
- DL ceased working Sept 2016
- VC ceased working Sept 2016
- FR ceased working Sept 2015
- JC ceased working Jan 2015
- RR ceased working Dec 2014
- CN ceased working Jan 2019
- BD ceased working Aug 2014
- GA ceased working Nov 2022
- SU ceased working May 2019
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 DTM instruments, the data are complete through May 2025. More data exist but have not been archived. In this archive, the data extend back to the time when the telemetry was changed to a newer model of digitizer and transmitter which occurred in early 2007. Typically, these data are recorded at 10-minutue intervals. For many of the DTM instruments, high sample rate, 200 sps, data exist as miniSeed files from NCEDC.org website.
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.
| Name | Code | Latitude | Longitude | Initial obs. | Instrument type | Notes | Pressure data | Gage data clean | Gage data adjusted | Tensor data clean | Tensor data adjusted |
|---|---|---|---|---|---|---|---|---|---|---|---|
Parkfield | |||||||||||
| Donna Lea | DLT | 35.9400 | -120.4250 | Jan. 1988 | | | | | | | |
| Frolich (2) | FLT | 35.9100 | -120.4900 | Mar. 1988 | | | | | | | |
| Eades (3) | EDT | 35.8900 | -120.4200 | Jan. 1988 | | | | | | | |
San Francisco Bay Area | |||||||||||
| Saint Vincents | SV | 38.0330 | -122.5260 | Jan. 2008 | | | | | | | |
| Ohlone | OH | 38.0070 | -122.2740 | Jan. 2008 | | | | | | | |
| Marin Headlands | MH | 37.8420 | -122.4940 | May-08 | | | | | | | |
| Chabot | CHT | 37.7430 | -122.0970 | Jun. 1993 | | | | | | | |
| Brisbane | BB | 37.6870 | -122.4100 | Apr. 2008 | | | | | | | |
| Garin (1) | GAT | 37.6500 | -122.0100 | Jan. 1993 | | | | | | | |
| Ox Mountain | OX | 37.4980 | -122.4250 | Jan. 2008 | | | | | | | |
| San Juan Bautista | SJT | 36.8370 | -121.5440 | Jan. 1984 | | | | | | | |
Southern California | |||||||||||
| Coldbrok | CBT | 34.2900 | -117.8400 | Jan-97 | | | | | | | |
| Pinon Flat (4) | PFT | 33.6200 | -116.4500 | Jan-83 | | | | | | | |
- Ceased working in Sep 1998
- Ceased working; second gage in Dec 2005
- Ceased working in Apr 2002
- Ceased working in Dec 2002