Active source tomography in northwestern Xinjiang, China: Implication for mineral distribution

Abstract

The main aim of this work is to understand the distribution of minerals by obtaining a shallow velocity structure around the Karatungk (喀拉通克) region. Data were acquired in 2009 by a denser array in deploying a transportable seismometer with 4.5 Hz vertical geophone. All the P-wave arrival times are picked automatically with Akaike information criterion, and then checked manmachine interactively by short-receiver geometry. The database for local active-source tomographic inversion involves 4 241 P-wave arrival time readings from 96 shots and three quarry blasts. Checkerboard tests aimed at checking the reliability of the obtained velocity models are presented. The resulting V _p distribution slices show a complicated 3-D structure beneath this area and offer a better understanding of three well-defined mineral deposits. Near the surface we observe a series of zones with slightly high-velocity which probably reflect potential deposits. Based on features of metallic ores we attempt to delimit their distributions and stretched directions.

Keywords

active source tomography / phase pick / shallow velocity structure / mineral distribution / optimization / 3-D iterative inversion

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