preliminary geological survey

基本解释

But no tsunami followed Wednesday's aftershocks, the magnitudes of which ran from 5.9 to 6.3 in preliminary readings by the U.S. Geological Survey.
但周三余震后并没有发生海啸。据美国地质调查局(U.S. Geological Survey)初步测定，余震震级从5.9到6.3级不等。
First, based on site survey, preliminary engineering geological evaluation on the wall rock was made and it was concluded that the wall rock was in unstable status.
首先，根据现场调查，对围岩进行了初步的工程地质评价，认为该岩体处于不稳定状态；
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Preliminary survey of the site finds that the area is flood land in geological structure. On this land suitable for setting up factory, no destructive earthquake has occurred before.
经现场初步踏勘，项目选址区属于河漫滩地，地质条件较好；历史上也不曾发作过毁坏性的地震，适合建厂。