Accession Number:

ADA278569

Title:

Single-Station Backazimuth Estimation from P- and Rg-Waves at Regional Distance in the Central Appalachians

Personal Author(s):

Corporate Author:

VIRGINIA POLYTECHNIC INST AND STATE UNIV BLACKSBURG DEPT OF GEOSCIENCES

Report Date:

1993-11-30

Abstract:

The study examines the accuracy of single-station backazimuth measurements from polarization analysis of near regional P- and Rg-wave arrivals. The data set consists of 37 signals from mining explosions in the distance range 100 to 300 km, recorded at station BLA, Blacksburg, Virginia. The station-source backazimuth estimates derived from the three component station are compared with results derived from independent information, primarily from regional network epicenter locations. For P-wave signalnoise ratios in excess of 2.0, the mean backazimuth error of the single-station estimate is 6 degrees for sources in the northwest quadrant and the standard deviation is 21 degrees. Generally, only the initial 1 second or less portion of the P-wave arrival is polarized in the source station azimuth. Off-azimuth arrivals consisting of converted and scattered energy appear early in the P coda. Emergent P-wave arrivals from the delay fired explosions, combined with steep apparent angles of incidence averaging 22 degrees complicate the single station, three component location problem. A subset of 27 signals featuring recognizable Rg arrivals was analyzed using a phase difference criterion. On average, the resulting backazimuth estimates are almost as reliable as those derived from the P-wave motion. Source-receiver backazimuth measurement, P-Wave polarization, Rg-Wave polarization.

Descriptive Note:

Final rept. 28 Mar-28 Sep 1993

Supplementary Note:

DOI: 10.21236/ADA278569

Pages:

0059

Descriptors:

Identifiers:

Subject Categories:

Communities Of Interest:

Distribution Statement:

Approved for public release; distribution is unlimited.

Contract Number:

F19628-92-K-0029

File Size:

1.96MB

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