Three Dimensional Velocity Images of the Crust and Upper Mantle
Beneath the North-South Zone in China with LSQR Inversion Method
Yike Liu and Xu Chang
Institute of Geophysics, Chinese Academy of Sciences,
11A Datun Road, Chaoyang District
Beijing, 100101, China, e-mail: ykliu@mail.c-geos.ac.cn, changxu@mail.c-geos.ac.cn
Abstract
Three-dimensional velocity images of the crust and upper mantle beneath
the North-South Zone are obtained by means of seismic tomography method
based on LSQR algorithm. An appraisal method for LSQR was proposed to
estimate resolution of the solution by the authors. The image results
indicate that there is a significant lateral heterogeneity in the crust and
upper mantle beneath the North-South zone persisting down to 450 km in
depth; the velocity images of the upper crust show the features closely
related to the well-known tectonic features on the surface; the low layer
exists in a very wide range of the mid-crust. The lowest velocity value is
near 5.60 km/s; in a long narrow piece of area between 25N-38N and
100.0E-103.2E, the low velocity anomaly about 7.49 km/s appears at the top
of the upper mantle. The image result at a depth of 120 km also outlines
clearly the welded boundaries between the different geological blocks.
raeg98@tansa.kumst.kyoto-u.ac.jp
Last modified: Tue Oct 6 09:55:44 1998