Accession Number:

ADA248255

Title:

Land-Based Seismic Array Studies of Low Frequency Ambient Oceanic Noise

Descriptive Note:

Final rept.,

Corporate Author:

TELEDYNE GEOTECH ALEXANDRIA VA ALEXANDRIA LABS

Personal Author(s):

Report Date:

1992-02-01

Pagination or Media Count:

44.0

Abstract:

Low frequency 0-01 to 0.2 Hz seismic noise, arising from pelagic storms, is commonly observed as microseisms in seismic records from land and ocean bottom detectors. One principal research objective, in the study of microseisms, has been to locate their sources. This paper reports on an analysis of primary and secondary microseisms recorded simultaneously on three land-based long-period arrays Alaskan Long Period Array, Montana Large Aperture Seismic Array, and Norwegian Seismic Array during the early 1970s. Reliable microseism source locations are determined by wide-angle triangulation, using the azimuths of approach obtained from frequency wave-number analysis of the records of microseisms propagating across these arrays. Two near-shore sources of both primary and secondary microseisms appear to be persistent in the sense that they are associated with essentially constant near-shore locations. Secondary microseisms are observed to emanate from wide ranging pelagic locations in addition to the same near-shore locations determined for the primary microseisms.

Subject Categories:

  • Physical and Dynamic Oceanography
  • Seismic Detection and Detectors

Distribution Statement:

APPROVED FOR PUBLIC RELEASE