Study of Magnitudes, Seismicity and Earthquake Detectability Using a Global Network
Abstract
Based on 10 years of observations reported in the International Seismological Center bulletins (1971-1980), m sub b magnitudes for about 70000 earthquakes have been recomputed using a maximum-likelihood estimation technique. Reporting from a network of 115 globally distributed stations were used in these calculations. Comparison to conventional m sub b estimates show that the network magnitude bias problem is quite significant at low and intermediate magnitudes. Recurrence statistics based on the revised m sub b estimates give b-values consistent with those obtained worldwide of m sub b > or = 4.0 averages about 7500 annually. The teleseismic detection capability of the network (requiring at least four detecting stations) has been estimated based on recurrence statistics. The estimated 90 per cent incremental m sub b threshold ranges from 3.9-4.5 in the northern hemisphere, and from 4.2-4.8 in the southern hemisphere. This is consistent with results obtained by the 'Networth' approach.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 1984
- Accession Number
- ADA173446
Entities
People
- Frode Ringdal
Organizations
- Leidos