This grant provides renewed partial support of operations of the International Seismological Center (ISC) over the four year period 2006-2010. For almost 40 years, the ISC has maintained a global summary (the ISC Bulletin) of earthquake hypocenters, magnitudes, moments and other hypocentral parameters, as well as arrival times, amplitudes and other phase measurements along with seismic array processing parameters for events of M > 3.5. The ISC Bulletin is available in hard copy, via CD-ROM and is now also web accessible. At the time of writing, the ISC database contained more than 34 Gb of information and in a typical month the ISC receives more than 3500 events with associated data from over 150,000 seismic recordings. NSF funding represents approximately 22% of the estimated annual operations and maintenance costs associated with the ISC. ISC tasks supported include: 1) analysis of hypocenters, phase readings, and related data including macroseismic reports for events from the 48 months period 2004 May - 2008 April; 2) distribution of the results from analysis in the Bulletin of the ISC in hard copy, CD-ROM and via the ISC web site; 3) maintenance of the International Registry of Seismic Stations; and 4) compilation of information about seismological institutions and seismologists and links to real-time earthquake and tsunami data centers available via the ISC web site. Researchers worldwide rely on the ISC Bulletin as the comprehensive catalog of earthquake and seismic event hypocenters. As a result the ISC indirectly supports international research in seismology, earthquake physics and tectonics. ISC activities represent a worldwide collaboration in geophysical research through the open availability of the ISC Bulletin. Research facilitated by use of Bulletin data has broad impact for earthquake hazards mitigation and for monitoring of the Comprehensive Test Ban Treaty. The ISC collects data from global, regional and local seismic networks worldwide. Data sets from some country networks would otherwise be inaccessible to U.S. seismologists if not through this independent, UK-based non-governmental institution.
