Accession Number : AD0676179

Title :   AZIMUTHAL DEPENDENCE OF GROUP VELOCITIES OF RAYLEIGH SURFACE SEISMIC WAVES BASED ON OBSERVATIONS IN SIMFEROPOL (AZIMUTALNAYA ZAVISIMOST GRUPPOVYKH SKOROSTEI POVERKHNOSTNYKH SEISMICHESKIKH VOLN RELEYA PO NABLYUDENIYAM V SIMFEROPOLE),

Corporate Author : FOREIGN TECHNOLOGY DIV WRIGHT-PATTERSON AFB OHIO

Personal Author(s) : Popov,I. I. ; Kapitanova,S. A.

Report Date : 16 NOV 1967

Pagination or Media Count : 10

Abstract : The results of observations of group velocity dispersion of Rayleigh surface waves conducted in the period 1957-1964 by the 'Simferopol' seismic station are presented. A standard SVK (Kirnos vertical system seismograph) was used in conjunction with a special long-period vertical seismograph to record 53 earthquakes whose foci were located in the Earth's crust and whose epicentral distances ranged from 3500 to 16,800 km. The magnitude of the earthquakes varied in the range 5 1/4 less than N less than 7 1/2, the periods of the dispersed waves were in the 10-100-sec interval, and the group velocities ranged from 2.7 to 4.6 km/sec. The azimutha from Simferopol' to the epicenters of most events were in the 0 to 90 degrees interval, i.e., originating in Eurasis. The technique of calculating the azimuthal dependance of group velocities by periods made it possible to determine the direction of the wave paths corresponding to external velocity values, thereby indicating the generation and propagation of surface waves from the block regions having the greatest crustal thickness or - in the case of longer period waves - of the upper mantle. (Author)

Descriptors :   (*SEISMOLOGICAL STATIONS, USSR), (*EARTHQUAKES, SEISMIC WAVES), SEISMOGRAPHS, EPICENTERS, VELOCITY, RAYLEIGH WAVES, AZIMUTH, PROPAGATION, THICKNESS, INTENSITY

Subject Categories : Seismology

Distribution Statement : APPROVED FOR PUBLIC RELEASE