REAL-TIME DOUBLE-DIFFERENCE EARTHQUAKE LOCATIONS FOR NORTHERN CALIFORNIA


Last updated on Fri May 16 21:49:01 UTC 2025    [DD-RT Version 2.0 | Contact: felixw@ldeo.columbia.edu]

IMPORTANT NOTE: A new comprehensive update of the Northern CA real-time double-difference catalog is available at https://nocaldd.ldeo.columbia.edu. The update includes a new base catalog (1984-2021) with hypocenter depths relative to the Geoid, consistent with USGS routine monitoring, and other improvements to the DD-RT system. We will retire this website soon.

How it works:
This website displays automatic near-real-time double-difference (DD-RT) hypocenter locations for earthquakes recorded in northern California and routinely processed at the Northern California Seismic Network (NCSN). The DD-RT process relocates new earthquakes relative to a high-resolution DD catalog of background seismicity, NCAeqDD, by using differential times between the new event and its neighboring (reference) events in the DD catalog. Routinely determined parametric data of new events, such as phase picks and hypocentral information, are automatically sent to LDEO by the NCSN and waveforms are accessed from the real-time DART server at the Northern California Earthquake Data Center (NCEDC) in Berkeley. Data associated with the reference events are accessed from a locally stored copy of the entire Northern CA seismic archive. See Waldhauser (BSSA, 2009) for more information. This web site is updated every 5 minutes.

Faults of special interest:
Hayward Fault | Calaveras Fault | Parkfield

Earthquakes of special interest:
2023-08-10 M4.3 Parkfield
2022-10-25 M5.0 Calaveras
2021-07-08 M6.0 SmithValley
2020-08-19 M4.0 Willits
2015-08-17 M4.0 Fremont
2014-08-24 M6.0 South Napa
2012-10-21 M5.3 King City
2012-08-06 M4.4 Parkfield
2011-10-20 M4.0 Berkeley

Archived DDRT solutions:
2012: Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec
2013: Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec
2014: Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec
2015: Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec
2016: Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec
2017: Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec
2018: Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec
2019: Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec
2020: Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec
2021: Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec
2022: Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec
2023: Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec
2024: Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec
2025: Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec

Downloads:
Download the real-time double-difference catalog, Jan 2012 - present, here .
Download the double-difference base catalog, 1984-2011, here.
Search either catalog here.

Most recent events:
Events in queue: 4
Q: Quality of DDRT solution; DX: Shift between DD and network location (km); V: version (CISN.DD)
If Q='-': No DDRT solution computed.
tech: link to technical information; 3D: link to 3D viewer; gE: link to google Earth viewer
Faults/regions of special interest:
HAY = Hayward Fault; CAL = Calaveras Fault; PKF = Parkfield; LVC = Long Valley;
GGF = Geysers Geothermal Field; MTJ = Mendocino TJ

EVENT ID DATE TIME (UTC) LAT LON DEPTH ML Q DX V
75182537 2025/05/15 20:02:58.970 37.52941 -118.62505 11.476 1.00 1 0.39 3F.1 tech 3D gE usgs LVC
75182467 2025/05/15 15:28:17.560 38.91045 -122.99841 2.442 1.00 1 0.99 2F.1 tech 3D gE usgs
75182437 2025/05/15 14:37:2.780 38.81778 -122.82305 3.509 0.40 2 0.78 2F.1 tech 3D gE usgs GGF
75182422 2025/05/15 13:51:2.370 39.16486 -123.16786 6.833 1.40 2 0.22 3F.1 tech 3D gE usgs
75182417 2025/05/15 13:50:32.010 39.54594 -123.37247 9.775 1.90 1 1.55 2F.1 tech 3D gE usgs
75182407 2025/05/15 12:27:54.730 38.81692 -122.81923 3.324 0.20 1 0.73 2F.1 tech 3D gE usgs GGF
75182322 2025/05/15 08:49:11.760 38.83827 -122.78388 2.780 0.40 1 0.78 2F.1 tech 3D gE usgs GGF
75182277 2025/05/15 06:46:18.180 38.83997 -122.79736 3.057 0.30 1 0.81 2F.1 tech 3D gE usgs GGF
75182257 2025/05/15 04:59:53.080 38.83325 -122.79478 3.075 0.30 2 0.93 2F.1 tech 3D gE usgs GGF
75182247 2025/05/15 04:37:34.980 38.52023 -119.49975 6.010 2.40 2 0.42 3F.1 tech 3D gE usgs
75182212 2025/05/15 03:10:57.200 39.39694 -120.24294 11.152 2.40 1 1.41 2F.1 tech 3D gE usgs
75182202 2025/05/15 02:24:7.510 38.83607 -122.81562 2.647 0.00 1 0.77 2F.1 tech 3D gE usgs GGF
75182192 2025/05/15 02:16:45.080 38.80108 -122.77677 4.903 0.30 1 1.17 2F.1 tech 3D gE usgs GGF
75182157 2025/05/15 01:24:16.980 40.03670 -123.77570 18.860 1.60 - - 2F.0 tech 3D gE usgs
75182127 2025/05/14 23:08:22.560 38.80476 -122.78034 3.914 0.00 2 1.04 2F.1 tech 3D gE usgs GGF
75182112 2025/05/14 22:23:48.000 37.66451 -121.67656 2.383 1.20 1 1.55 3F.1 tech 3D gE usgs
75182087 2025/05/14 21:30:4.160 38.80583 -122.79704 4.104 0.50 1 0.83 2F.1 tech 3D gE usgs GGF
75182047 2025/05/14 19:15:24.670 37.63170 -119.02880 -2.840 0.40 - - 3F.0 tech 3D gE usgs LVC
75182042 2025/05/14 19:13:2.320 38.84013 -122.78267 2.601 0.20 1 0.93 2F.1 tech 3D gE usgs GGF
75182027 2025/05/14 18:06:2.810 38.78383 -122.73214 2.465 0.50 1 0.63 2F.1 tech 3D gE usgs GGF

Events last re/processed:
75179101 2025/05/09 22:38:33.380 36.05880 -120.63183 0.926 1.00 2 0.71 4F.1 tech 3D gE usgs PKF
75179101 2025/05/09 22:38:33.520 36.05900 -120.62870 0.050 0.90 - - 2F.0 tech 3D gE usgs
75179081 2025/05/09 21:21:58.080 36.59132 -121.04487 8.832 1.00 2 2.92 3F.1 tech 3D gE usgs
75182537 2025/05/15 20:02:58.970 37.52941 -118.62505 11.476 1.00 1 0.39 3F.1 tech 3D gE usgs LVC
75176201 2025/05/04 04:46:33.340 38.82179 -122.80505 2.551 1.30 1 0.87 2F.1 tech 3D gE usgs GGF
75176176 2025/05/04 03:15:43.770 38.83517 -122.79283 2.527 1.00 1 0.93 2F.1 tech 3D gE usgs GGF
75176151 2025/05/04 01:24:26.620 38.83447 -122.79958 2.968 1.50 1 0.79 2F.1 tech 3D gE usgs GGF
75179531 2025/05/10 20:52:58.870 40.34200 -124.82620 12.940 2.10 - - 2F.0 tech 3D gE usgs MTJ
75178996 2025/05/09 17:49:9.920 40.30950 -124.95380 10.000 2.50 - - 2F.0 tech 3D gE usgs MTJ
75178801 2025/05/09 06:09:23.050 40.34020 -124.65820 23.040 2.50 - - 2F.0 tech 3D gE usgs MTJ


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Data sources: U.S. Geological Survey, Menlo Park; University of California, Berkeley; California Institute of Technology; University of Nevada, Reno; California Division of Water Resources; University of Utah; University of Southern California. Real-time data from the Northern California Seismic Network (NCSN) (parametric) and the Northern California Earthquake Data Center (NCEDC) (waveforms).
Project funded by USGS under its NEHRP program (06HQGR0054,08HQGR0043).
Website developed and maintained by Felix Waldhauser and Ben Engebreth at LDEO, Columbia University.