Advanced National Seismic System

Introduction to the ANSS:

The Advanced National Seismic System (ANSS) provides accurate and timely data and information products for seismic events, including their effects on buildings and structures, employing modern monitoring methods and technologies.

As part of its monitoring activities, the ANSS includes a national Backbone network, the National Earthquake Information Center (NEIC), the National Strong Motion Project, and 15 regional seismic networks operated by the United States Geological Survey (USGS) and its partners. When earthquakes strike, ANSS delivers real-time information, providing situational awareness for emergency-response personnel. In regions with sufficient seismic stations, that information includes–within minutes–a ShakeMap showing the distribution of potentially damaging ground shaking, information used to target post-earthquake response efforts. When fully implemented, ANSS will provide such dense station coverage for all at-risk urban areas. Information from ANSS is a key input to the USGS National Seismic Hazard Maps, which help communities in earthquake-prone regions develop safer building practices.


The California Integrated Seismic Network (CISN) is one of the regional networks that make up the ANSS. Currently, the EEW algorithms are being tested by data collected by the CISN.

The CISN goals are:

  • Operate a reliable and robust statewide system to record earthquake ground motions over the relevant range of frequencies and shaking levels
  • Distribute information about earthquakes rapidly after their occurrence for emergency response and public information
  • Create an easily accessible archive of California earthquake data for engineering and seismological research, including waveform data and derived products
  • Maintain CISN infrastructure as a reliable state-of-the-art data collection, processing, and information distribution system
  • Apply the latest research and technology to develop new algorithms for analyzing earthquake data and extracting more detailed information for new user products
  • Maximize the use and benefit of real-time seismic information and other rapidly evolving tools and technologies through technology transfer to the user community

Six organizations have collaborated to form the CISN in order to further the goals of earthquake monitoring. The founding members of the CISN include: California Geological Survey, Caltech Seismological Laboratory, Berkeley Seismological Laboratory, USGS Menlo Park, USGS Pasadena, and the California Governor’s Office of Emergency Services. In addition to the core members, several organizations contribute data that enhances the capabilities of the CISN. Contributing members of the CISN include: University of California, Santa Barbara, University of California, San Diego, University of Nevada, Reno, University of Washington, California Department of Water Resources, Lawrence Livermore National Lab, and Pacific Gas and Electric.

Read about the seismic instrumentation used in EEW