The IRIS Global Seismographic Network (GSN) is one of the four
major components of the IRIS Consortium. The goal of the GSN is
to deploy 128 permanent seismic recording stations uniformly
over the ... earth's surface.
As of 2001 the GSN was made up of over 120 stations with
affiliations to IRIS USGS, IRIS IDA, GEOFON, Pacific21, NCDSN,
MedNet, BGR, BFO, USNSN, BDSN and several other national and
international networks. Thirteen new stations are planned for
completion in 2001/2002.
The IRIS GSN stations continuously record seismic data from very
broad band seismometers at 20 samples per second. It is also the
goal of the GSN to record data with a dynamic range of 140 db
(24 bit digitizers). Nearly all of the IRIS GSN stations meet
More info at http://www.iris.washington.edu/GSN/
[Source: The IRIS Consortium]