A New Datum for use in the Body Wave Travel Time Inverse Problem

Autor: Freeman Gilbert, Leonard E. Johnson
Rok vydání: 1972
Předmět:
Zdroj: Geophysical Journal International. 30:373-380
ISSN: 1365-246X
0956-540X
Popis: Summary The traditional seismological data set, consisting of seismic ray data, is considered in this report. A new dependent parameter, T-pA, is introduced to enable one to deal effectively with multiplicities in the T(A) data. When the independent parameter is chosen to be the ray parameter, p, the new dependent parameter can be calculated from existing seismic ray data with errors that are second order in p. 1. Traditional data The traditional seismological data used in the body wave travel time inverse problem are values of p(A) where (see Fig. 1) A is the angular distance separating the source and receiver, and p (p = u-' Y sin i) is called the ray parameter. By Snell's law, p is constant along the ray. It can be shown that p = dT/dA (Bullen 1963, p. 110) where T is the travel time from a source to a receiver. Given a set of data consisting of observed values of T(A) or p(A) for several seismic phases generated at a number of sources and measured by a number of receivers, what can be inferred about the seismic velocity u(r) within the Earth? To solve an inverse problem, it is necessary first to solve the direct problem. In this case, this amounts to calculating the travel time, Ti, for any model given a source-receiver separation Ai. The numerical computations involved in the direct
Databáze: OpenAIRE
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