Northern California Seismic System

About the NCSS

The Northern California Seismic System (NCSS) is the collaboration between the UC Berkeley Seismological Laboratory (BSL) and U.S. Geological Survey (USGS) at Menlo Park to provide reliable, real-time earthquake information for Northern and Central California as part of the California Integrated Seismic Network (CISN). For this purpose, the NCSS combines data from seismic networks operated by both institutions as well as other partner and contributing networks.


The first seismic instruments were deployed in California by UC Berkeley on its campus and at Mt. Hamilton's Lick Observatory in 1887. In the following years, the university developed a sparse, regional network in northern and central California and reported on seismicity in the area. In 1966, following the Parkfield earthquake, the USGS expanded its seismic network for micro-earthquake studies to also cover Northern and Central California. Later, in 1990, UC Berkeley and the USGS began collaborating on joint projects related to the collection and availability of earthquake data and information, such as the Northern California Earthquake Data Center. Since that time, the collaborative activities have in multiplied, with current earthquake reporting a joint effort. The following stepping stones lead to the current status.

1996 - BSL and USGS began collaborating to produce information for Northern and Central California earthquakes. Software operating in Berkeley and Menlo Park were merged (daisy-chained?) to form a single, improved earthquake notification system using data from both the Northern California Seismic Network (NCSN) and the Berkeley Digital Seismic Network (BDSN). Together, BSL and USGS provide the most complete data available for an earthquake to include its location, magnitude, focal mechanism, fault rupture characteristics, and ground shaking distribution.

2000 - BSL and USGS Menlo Park began operating as the Northern California Earthquake Management Center (NCEMC) as part of the California Integrated Seismic Network (CISN). The NCEMC is one of two statewide earthquake processing centers; the Southern California Earthquake Management Center (SCEMC), which is comprised of Caltech and USGS Pasadena, is the other.

2009 - BSL and USGS Menlo Park began operating complete earthquake information processing and analysis systems in parallel. Incoming data from BSL, USGS, and other partner networks are processed locally, and in real time, at each of the two institutions using the ANSS Quake Monitoring System, or AQMS, software. To maintain redundancy, two databases replicate with each other and also with a third database through which information is made available to the public.

2010s - The number of earthquakes detected and located by the automatic systems in Northern California continues to increase:

  • Fiscal year 2010-2011: 25,000 events
  • Fiscal year 2011-2012: 27,000 events
  • Fiscal year 2012-2013: 32,000 events
  • Fiscal year 2013-2014: 35,000 events

2016 - BSL and USGS Menlo Park began running the Earthquake Early Warning (EEW) System (in prototype production mode) in conjunction with the AQMS earthquake information system. The fully developed system will cover California, Oregon, and Washington, and will provide warning of imminent ground shaking within seconds after an earthquake has initiated but before strong motion begins at many sites that may be damaged. While still in development, the EEW system has produced alerts for several earthquakes in the Los Angeles area less than five seconds after the earthquake has started.

About the NCEDC

The Northern California Earthquake Data Center (NCEDC) is the permanent archive and distribution center for many types of digital data relating to earthquakes in central and northern California. The NCEDC is located at the Berkeley Seismological Lab (BSL) and was formed as a joint project of BSL and the U.S. Geological Survey (USGS) at Menlo Park in 1991. It has been accessible to users via the Internet since mid-1992.

The NCEDC archives and makes available both time series data and earthquake catalog information. The time series data come from from broadband, short period, and strong motion seismic sensors, as well as other geophysical sensors such as electromagnetic sensors, strain meters, creep meters, atmospheric pressure, pore pressure, water level, and wind speed sensors. Earthquake catalog data include event time, hypocenters, magnitudes, moment tensors, mechanisms, phase arrivals, codas, and amplitude data. Real time and campaign GPS data are also available.

Products and Services

Latest Earthquakes in California and Nevada
Interactive map showing recent earthquakes in California

ShakeMap is a product of the USGS Earthquake Hazards Program in conjunction with the regional seismic networks. ShakeMaps provide near-real-time maps of ground motion and shaking intensity following significant earthquakes. These maps are used by federal, state, and local organizations, both public and private, for post-earthquake response and recovery, public and scientific information, as well as for preparedness exercises and disaster planning.

The U. S. Geological Survey (USGS) along with a coalition of State and university partners is developing and testing an earthquake early warning (EEW) system called ShakeAlert for the west coast of the United States. Long term funding must be secured before the system can begin sending general public notifications, however, some limited pilot projects are active and more are being developed. The USGS has set the goal of begining limited public notifications by 2018.

Did You Feel It?
Did You Feel It? (DYFI) collects information from people who felt an earthquake and creates maps that show what people experienced and the extent of damage.

Links to Data Centers and Catalogs

Northern California Earthquake Data Center

Northern California Earthquake Catalog Search at the NCEDC.

ANSS Composite Catalog Search at the NCEDC

Southern California Earthquake Date Center

Southern California Seismic Network Catalog Search at the SCEDC

National Strong Motion Project

Download Strong Motion Data at Center for Engineering Strong Motion Data

Incorporated Research Institutions for Seismology