Accession Number : AD0625966

Title :   RESEARCH DIRECTED TOWARD THE STUDY OF SEISMICITY IN THE SOUTHEASTERN UNITED STATES.

Descriptive Note : Annual technical rept., no. 2,

Corporate Author : RESEARCH TRIANGLE INST DURHAM N C

Personal Author(s) : Minear,John W.

Report Date : 05 JAN 1966

Pagination or Media Count : 35

Abstract : Principle research activities during the period of December 15, 1964 to December 15, 1965 were concerned with (1) local epicenter location, (2) long range refraction, (3) computation of crustal models from gravity data and surface wave dispersion, and (4) computation of P-Residuals. Several epicenters were located in the Southern Applachians using data from Vela standard and mobile stations. P-Residuals have been computed for about 500 earthquakes recorded at Chapel Hil, North Carolina and the Cumberland Plateau Seismological Observatory. A systematic sinusoidal deviation of the residuals with epicentral distance has been observed. Magnitude, focal depth, and energy release for several earthquakes previously reported have been calculated. Estimates of crustal thickness in the Southeastern United States from gravity data using the basic sin x/x method have been made. A derivation of the sin x/x method using the concept of sampling by an infinite Dirac comb is developed. Results of refraction work in North Carolina using local quarry blasts is presented. Some preliminary results of participation in the East Coast On-Shore OffShore Experiment are also given. Several computer programs were developed during the course of study. These include epicenter location, P-Residual computation, mass anomaly computation from gravity anomalies, autoregression of time-series data, and the computation of phase velocities by bandpass filtering. (Author)

Descriptors :   (*SEISMOLOGY, NORTH CAROLINA), (*EARTHQUAKES, UNITED STATES), EPICENTERS, POSITION FINDING, SEISMIC WAVES, PROPAGATION, STRUCTURAL GEOLOGY

Subject Categories : Seismology

Distribution Statement : APPROVED FOR PUBLIC RELEASE