Open AccessInversion for V P / V s in Shallow Source Regions
Author(s) -
Fitch Thomas J.,
Rynn John M. W.
Publication year - 1976
Publication title -
geophysical journal of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.302
H-Index - 168
eISSN - 1365-246X
pISSN - 0016-8009
DOI - 10.1111/j.1365-246x.1976.tb00285.x
Subject(s) - geology , seismology , inversion (geology) , crust , shear (geology) , geodesy , geophysics , tectonics , petrology
Summary A scheme for joint location of a group of closely‐spaced earthquakes has been evolved to give estimates of the ratio of compressional to shear velocities in the source region. Solutions with synthetic data support a claim that nearly unbiased estimates of V P / V S are possible even if the same solution contains strongly biased earthquake locations. Real data to test this inversion scheme are arrival times of P and S waves from two groups of microearthquakes located within the crust and east of the Alpine fault in New Zealand; these times are read to ±0.1 s. In both source regions V P / V S is about 7 per cent less than a regional average ratio of 1.64 derived from the same data using plots of S‐P versus P times.