Towards a Global Seismic Monitoring System — Lessons Learned from Geneva Experiments

Abstract

This lecture summarizes results from technical experiments conducted by the GSE (Group of Scientific Experts) in Geneva over the past 15 years. It shows the interrelation between conceptual design of an international seismic data exchange system and technical developments in instrumentation and communication channels. Although the GSE-experiments have given valuable experience in many technical aspects of a seismological monitoring system, a full scale test still awaits the existence of a calibrated station network.

With the experience from previous experiments, the GSE recently re-assessed the concept of the seismological monitoring system. The new concept includes: a single centralized international data centre (IDC); a specifically designed high-quality station network; and a modern communications system providing continuously waveform data to the IDC. To test this modernized concept, a very ambitious experiment (GSETT-3) has already started in 1993 with full-scale operational testing scheduled to begin in January 1995. GSETT-3 will be an unprecedented global effort to conduct an operationally realistic test of rapid data collection, distribution and processing. Previous GSE experiments have shown, however, that the use of modern technology does not necessarily improve the seismological results. Lessons learned from the seismological evaluation of GSETT-2 should be reminded. The most important aspect is that the seismological monitoring system can evolve. The system evolution will not be restricted to technical elements but it will also include improvements in the seismological capabilities when the station network has been calibrated with respect to global and regional travel-time curves and amplitudedistance relations. Other areas where further work is needed, include enhancement of phase identification and phase association, event location procedures and event characterization.