HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) References Citation Map Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by SCHERBAUM, F. Articles by KISSLINGER, C. Search for Related Content GeoRef GeoRef Citation

Variations of apparent stresses and stress drops prior to the earthquake of 6 May 1984 (m_b = 5.8) in the Adak Seismic Zone

COOPERATIVE INSTITUTE FOR RESEARCH IN ENVIRONMENTAL SCIENCES UNIVERSITY OF COLORADO, BOULDER, COLORADO 80309
INSTITUT FUER GEOPHYSIK DER UNIVERSITAET, STUTTGART, RICHARD WAGNER STR. 44,, 7000 STUTTGART, Federal Republic of Germany

Abstract

On 6 May 1984, a m_b = 5.8 earthquake occurred within a subregion of the Adak Seismic Zone that had shown clustering of m_b>4.5 earthquakes during the last 3 yr. This region has been examined for premonitory variations in stress drop and apparent stresses, calculated from the S-wave spectra of 69 microearthquakes (M_d < 2.7) which occurred between January 1981 and May 1984. The influence of local site conditions seems to control the corner frequencies at certain stations. Both the distribution of apparent stresses and stress drops shows local concentrations of high values close to the hypocenter of the 6 May event and an increase with time over 3 yr for earthquakes closer than 7.5 km. The significance of the increase is greater than 99.5 percent for the apparent stresses and greater than 95 percent for the stress drops. The quantitative interpretation in terms of ambient stresses is aggravated since the stress drops with seismic moments less than about 1.0 x 10¹³ Nm decrease with decreasing moment.

This article has been cited by other articles:

				Source Spectral Scaling and Stress Release Estimates Using Strong-Motion Records in Greece Bulletin of the Seismological Society of America, April 1, 2002; 92(3): 1040 - 1059.

				V. M. Zobin Apparent stress of earthquakes within the shallow subduction zone near Kamchatka Peninsula Bulletin of the Seismological Society of America, June 1, 1996; 86(3): 811 - 820. [Abstract] [PDF]

				C. KISSLINGER An experiment in earthquake prediction and the 7 May 1986 Andreanof Islands earthquake Bulletin of the Seismological Society of America, February 1, 1988; 78(1): 218 - 229. [Abstract] [PDF]

				F. SCHERBAUM Seismic imaging of the site response using microearthquake recordings. Part I. Method Bulletin of the Seismological Society of America, December 1, 1987; 77(6): 1905 - 1923. [Abstract] [PDF]

				G. DE NATALE, R. MADARIAGA, R. SCARPA, and A. ZOLLO Source parameter analysis from strong motion records of the Friuli, Italy, earthquake sequence (1976-1977) Bulletin of the Seismological Society of America, August 1, 1987; 77(4): 1127 - 1146. [Abstract] [PDF]

				F. R. ZUNIGA, M. WYSS, and M. E. WILSON Apparent stresses, stress drops, and amplitude ratios of earthquakes preceding and following the 1975 Hawaii MS = 7.2 main shock Bulletin of the Seismological Society of America, February 1, 1987; 77(1): 69 - 96. [Abstract] [PDF]

				F. SCHERBAUM and C. KISSLINGER Coda Q in the Adak seismic zone Bulletin of the Seismological Society of America, April 1, 1985; 75(2): 615 - 620. [PDF]