Premium
Three‐dimensional υ p and υ p /υ s structure of the Hengill Triple Junction and Geothermal Area, Iceland, and the repeatability of tomographic inversion
Author(s) -
Foulger G. R.,
Miller A. D.,
Julian B. R.,
Evans J. R.
Publication year - 1995
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/94gl03387
Subject(s) - geothermal gradient , triple junction , repeatability , geology , instrumentation (computer programming) , seismology , mineralogy , geophysics , chemistry , chromatography , computer science , operating system
We investigate the crustal structure of the Hengill triple junction in southwestern Iceland, applying tomographic methods to local earthquake data recorded in two field experiments with different network geometries and instrumentation. Data from the two experiments enable us to derive three‐dimensional models of the compressional‐wave speed υ p and the wave‐speed ratio υ p /υ s . Well resolved high‐υ p bodies correlate with sites of gabbroic intrusions. A small reduction in υ p /υ s associated with the high‐temperature part of the geothermal area is probably due to mineral alteration or supercritical fluids. The RMS difference between the two υ p models, about 0.26 km s −1 , indicates the approximate repeatability that may be expected of good tomographic inversions.