The Global Seismographic Network (GSN) is a permanent, digital network of more than 150 modern stations in over 80 countries, from the South Pole to Siberia and from the Pacific basin to the southern tip of Africa. At the core of the GSN, are the very broadband, high-dynamic range seismometers that measure the vibrations of the Earth. These instruments are extremely sensitive over a wide range of frequencies and are capable of detecting the response of the Earth to the motions of the Sun and the Moon with periods of thousands of seconds, as well as the strong shaking near large earthquakes with periods less than a tenth of a second, with high fidelity.

In many cases, these seismometers are combined with other sensors, such as microbarographs, anemometers, magnetometers, and Global Positioning System receivers, to form geophysical observatories. Advanced systems for data acquisition and communications transmit continuous digital data from the stations to collection points in the U.S.

The GSN was formed in 1986 as a partnership involving the U.S. Geological Survey (USGS), the National Science Foundation (NSF), and the Incorporated Research Institutions for Seismology (IRIS, a university consortium) and serves as a multi-use scientific facility and societal resource for monitoring, research, and education. All GSN data are freely and openly available to the public and scientists around the world from the IRIS Data Management Center.

First posted June 14, 2011