REAL-TIME DOUBLE-DIFFERENCE EARTHQUAKE LOCATIONS FOR NORTHERN CALIFORNIA


Last updated on Tue Jul 1 06:49:57 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: 0
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
75202946 2025/07/01 05:55:40.310 37.70919 -121.97760 9.255 3.00 1 2.69 3H.1 tech 3D gE usgs
75202936 2025/07/01 05:32:24.390 39.59870 -121.44280 18.620 1.80 - - 0A.0 tech 3D gE usgs
75202931 2025/07/01 05:29:19.290 38.73229 -122.93708 2.230 1.00 2 0.67 0A.1 tech 3D gE usgs
75202926 2025/07/01 04:59:39.420 37.25220 -121.63623 5.269 1.70 1 0.65 0A.1 tech 3D gE usgs CAL
75202921 2025/07/01 04:09:2.850 38.81829 -122.84795 3.114 0.30 2 0.91 0A.1 tech 3D gE usgs GGF
75202916 2025/07/01 03:16:32.370 38.83524 -122.79767 2.429 0.20 1 0.73 0A.1 tech 3D gE usgs GGF
75202911 2025/07/01 02:55:19.840 36.01452 -120.09414 4.765 2.40 2 0.25 0A.1 tech 3D gE usgs
75202906 2025/07/01 02:26:50.950 38.81990 -122.76156 2.743 0.80 1 0.95 0A.1 tech 3D gE usgs GGF
75202901 2025/07/01 02:11:47.540 38.84136 -122.82228 2.859 1.20 2 0.86 0A.1 tech 3D gE usgs GGF
75202891 2025/07/01 02:09:10.840 37.04150 -121.13050 1.950 1.40 - - 0A.0 tech 3D gE usgs
75202886 2025/07/01 01:37:54.580 37.03812 -121.12819 0.808 3.50 1 1.04 4F.1 tech 3D gE usgs
75202881 2025/07/01 01:16:3.700 38.82028 -122.84539 3.239 0.90 2 0.96 0A.1 tech 3D gE usgs GGF
75202876 2025/07/01 01:05:10.090 38.83521 -122.82026 2.576 1.90 1 0.92 0A.1 tech 3D gE usgs GGF
75202856 2025/07/01 00:32:11.380 38.83122 -122.79666 4.117 0.80 2 1.31 0A.1 tech 3D gE usgs GGF
75202836 2025/07/01 00:08:12.980 38.72300 -123.03130 12.440 1.20 - - 0A.0 tech 3D gE usgs
75202831 2025/07/01 00:04:19.740 40.21130 -124.15500 1.920 0.90 - - 0A.0 tech 3D gE usgs MTJ
75202826 2025/06/30 23:59:16.330 38.41430 -122.60780 4.280 0.00 - - 0A.0 tech 3D gE usgs
75202821 2025/06/30 23:50:9.350 38.82442 -122.85709 2.728 0.30 2 0.50 0A.1 tech 3D gE usgs GGF
75202801 2025/06/30 22:35:35.740 38.78887 -122.89264 9.565 0.80 2 0.34 0A.1 tech 3D gE usgs GGF
75202786 2025/06/30 22:24:59.890 38.76287 -122.69596 3.059 0.70 1 1.49 0A.1 tech 3D gE usgs GGF

Events last re/processed:
75201881 2025/06/28 20:15:51.890 37.15849 -122.40680 10.764 1.30 2 0.17 2F.1 tech 3D gE usgs
75202946 2025/07/01 05:55:40.310 37.70919 -121.97760 9.255 3.00 1 2.69 3H.1 tech 3D gE usgs
75202886 2025/07/01 01:37:54.580 37.03812 -121.12819 0.808 3.50 1 1.04 4F.1 tech 3D gE usgs
75201856 2025/06/28 18:09:0.690 36.99340 -121.65663 3.739 1.20 1 0.67 3F.1 tech 3D gE usgs
75201856 2025/06/28 18:09:0.690 36.99340 -121.65663 3.739 1.20 1 0.67 2F.1 tech 3D gE usgs
75202936 2025/07/01 05:32:24.390 39.59870 -121.44280 18.620 1.80 - - 0A.0 tech 3D gE usgs
75202931 2025/07/01 05:29:19.290 38.73229 -122.93708 2.230 1.00 2 0.67 0A.1 tech 3D gE usgs
75202926 2025/07/01 04:59:39.420 37.25220 -121.63623 5.269 1.70 1 0.65 0A.1 tech 3D gE usgs CAL
75202921 2025/07/01 04:09:2.850 38.81829 -122.84795 3.114 0.30 2 0.91 0A.1 tech 3D gE usgs GGF
75202916 2025/07/01 03:16:32.370 38.83524 -122.79767 2.429 0.20 1 0.73 0A.1 tech 3D gE usgs GGF


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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.