Accession Number:

ADA231804

Title:

Analysis of High Frequency Seismic Data

Descriptive Note:

Rept. for 1 Oct 1988-1 Oct 1989

Corporate Author:

SCIENCE APPLICATIONS INTERNATIONAL CORP (SAIC) ARLINGTON VA CENTER FOR SEISMIC STUDIES

Report Date:

1990-10-01

Pagination or Media Count:

159.0

Abstract:

The focus of the research is on the detection, location, and identification of seismic events using high frequency seismic data. Data for these studies come primarily from the NORESS small aperture array in Norway and its high frequency up to 125 Hz central element, and the high-frequency stations installed close to the Eastern Kazakhstan test sites. The first section is an examination of the NORESS data to be used in this project. Mining is found to be a major source of seismic signal in Fennoscandia with large concentrations of activity on the Kola Peninsula, Southern Norway, and Central Sweden. In section three, a method is developed for estimating the rolloff and scaling parameter for corner frequency-seismic moment from spectral ratios of a suite of events from the same location and with the same source function. Section four contains studies of the characterization of earthquakes and mine blasts. Inter- event correlation of mine blasts is shown to constrain the relative locations of events to very small distances 100m at 15 Hz. The effect of scatter in the delays of ripple fired quarry blasts are examined theoretically and illustrate that a 20 scatter can significantly attenuate the secondary harmonics of the spectrum and reduce the signal-to-noise ratio of the primary peak. The final section is a short note on the instrument responses of the NRDC stations and the Special Data Collection System used to monitor the Nevada test site. Because the response of the two systems are similar in the teleseismic frequency band 1 to 3 Hz, magnitudes obtained from the two different system can be compared in a gross sense.

Subject Categories:

  • Seismic Detection and Detectors

Distribution Statement:

APPROVED FOR PUBLIC RELEASE