3-DIMENSIONAL UPSILON (P), AND UPSILON (P) UPSILON (S) STRUCTURE OF THE HENGILL TRIPLE JUNCTION AND GEOTHERMAL AREA, ICELAND, AND THE REPEATABILITY OF TOMOGRAPHIC INVERSION/
Gr. Foulger et al., 3-DIMENSIONAL UPSILON (P), AND UPSILON (P) UPSILON (S) STRUCTURE OF THE HENGILL TRIPLE JUNCTION AND GEOTHERMAL AREA, ICELAND, AND THE REPEATABILITY OF TOMOGRAPHIC INVERSION/, Geophysical research letters, 22(10), 1995, pp. 1309-1312
We investigate the crustal structure of the Hengill triple junction in
southwestern Iceland, ap plying tomographic methods to local earthqua
ke data recorded in two held experiments with different network geomet
ries and instrumentation. Data from the two experiments enable us to d
erive three-dimensional models of the compressional-wave speed v(p), a
nd the wave-speed ratio v(p)/v(s). Well resolved high-v(p) bodies corr
elate,with sites of gabbroic intrusions. A small reduction in v(p)/v(s
) associated with the high-temperature part of the geothermal area is
probably due to mineral alteration or supercritical fluids. The RMS di
fference between the two v(p) models, about 0.26 km s(-1), indicates t
he approximate repeatability that may de expected of good tomographic
inversions.