Precursors to PP

Abstract

The results of a theoretical study of the interpretation of precursors to PP (delta approximately equals 100 deg) in terms of scattering by small-scale random irregularities in the crust and uppermost mantle are presented. These results are compared with observational data from two nuclear explosions recorded at the Warramunga array and three earthquakes recorded at the NORSAR array. This comparison reveals that the scattering interpretation offers a plausible and adequate explanation of the detailed observational data, namely: onset times, duration, slowness, azimuth and amplitude variations. The scattering interpretation of PP precursors, along with a similar interpretation of precursors to PKPPKP, removes the need for postulating sharp reflecting discontinuities in the uppermost few hundred kilometers of the crust and upper mantle.

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Document Details

Document Type
Technical Report
Publication Date
Feb 28, 1975
Accession Number
ADA008180

Entities

People

  • D. W. King
  • E. S. Husebye
  • R. A. W. Haddon

Organizations

  • Royal Norwegian Council for Scientific and Industrial Research

Tags

Communities of Interest

  • Air Platforms
  • Energy and Power Technologies

DTIC Thesaurus Topics

  • Abstracts
  • Air Force
  • Amplitude
  • Arrays
  • Discontinuities
  • Explosions
  • Intensity
  • Measurement
  • Nuclear Explosions
  • Pattern Recognition
  • Precursors
  • Scattering
  • Seismic Arrays
  • Seismic Waves
  • Steady State
  • Time Intervals
  • Travel Time

Readers

  • Seismology
  • Theoretical Analysis.