The Norwegian Seismic Array (NORSAR). Phase 3
Abstract
The NORSAR Detection Processing System has been operated throughout the reporting period with an average uptime of 98.2 per cent. A total of 1577 seismic events has been reported. The performance of the continuous alarm system and the automatic bulletin transfer by telex to AFTAC has been satisfactory. On- line NORESS detection processing and data recording at the NORSAR Data Center (NDPC) has been conducted throughout the period. A study has been conducted focusing on the problem of determining accurate yields for explosions at the Shagan River test site. The emphasis of the study is on assessing the combined utility of three methods to obtain relative yields of explosions. In addition, the estimation of absolute yields from the available seismic information is addressed, using the cratering explosion of 15 January 1965 for calibration purposes. The study reconfirms conclusions from earlier work regarding variations in mb-mLg bias across the Shagan area, and shows that this variation can be correlated with surface geological features. A method is developed to use seismic network recordings to continuously monitor the seismic noise field. The purpose is to determine to which extent interfering events affect the monitoring of events within a target region. A model that can be used to obtain, at a given confidence level, a continuous assessment of the upper limit of magnitudes of seismic events in the target region that would go undetected by such a network. (JHD)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 01, 1989
- Accession Number
- ADA217830
Entities
People
- L. B. Loughran
Organizations
- Royal Norwegian Council for Scientific and Industrial Research