Earthquake Focal Mechanisms from Relative Amplitudes of P, pP and sP: Method and Computer Program,

Abstract

This report describes a FORTRAN computer program which determines the orientation (with confidence limits) of an assumed double couple earthquake source, given a series of teleseismically observed relative amplitudes, each of which relates the amplitudes of either P and p superscript p and sP, or p superscript P and sP on one seismogram. Appropriate upper and lower limits are assigned in arbitrary units to the observed amplitude of each phase, with or without a polarity specification, and from these limits the program computes the corresponding range(s) of relative amplitudes for each pair of phases. All source orientations which are compatible with the range(s) of relative amplitudes are then identified, and can be displayed graphically. Those orientations which are compatible with all pairs of phases at all stations constitute the focal mechanism solution, with confidence limits which correspond directly to the confidence of the initial measurements. The program can be applied to shallow or deep earthquakes beneath land or sea. (Author)

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Document Details

Document Type
Technical Report
Publication Date
Aug 01, 1979
Accession Number
ADA085775

Entities

People

  • R. G. Pearce

Organizations

  • Atomic Weapons Establishment

Tags

Communities of Interest

  • Air Platforms
  • Weapons Technologies

DTIC Thesaurus Topics

  • Algorithms
  • Computations
  • Computer Programs
  • Computers
  • Confidence Limits
  • Data Sets
  • Doppler Effect
  • Equations
  • Far Field
  • Identification
  • Measurement
  • Multiplication Factor
  • Polarity
  • Radiation Patterns
  • Stations
  • Three Dimensional
  • Waves

Readers

  • Control Systems Engineering.
  • Seismology
  • Systems Analysis and Design