科研之友
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摘要
We carried out a numerical computing using FEM and FDM to simulate the migration of magma which ascends from crustal magma chamber along existing fault under tectonic stress and its buoyancy. On the top of a chamber, due to tiny crack, magma can be driven into the crack under some certain overpressure and moves up so the crack extends further and a channel for magma migration forms. We made a research on the critical overpressure which can drive magma up under given magma viscosity. For 0. 1 Pa . s to 10(3) Pa . s of magma viscosity at about 10 km depth in the crust, magma can be driven up by magma pressure to surface when the overpressure reaches 17 similar to 20 MPa, and the larger the viscosity, the higher the critical overpressure. It has been viewed that density difference, which means the difference of effective density of country rock and density of magma, from 300 to 700 kg . m(-3), influenced overpressure little. Making a comparison of different results between model 3-D and model 2-D, we find out distinctive vertical displacement on surface. Considering regional geologic environment of Changbaishan Tianchi volcano, after parameters testing and computing analysis, we estimated the volume of the chamber which could exist under Changbaishan Tianchi volcano on the condition of our model that provides some certain overpressure and no severe tectonic stress change. This result might provide some reference for magma activity and relevant prediction and monitoring for Changbaishan Tianchi volcano region.
- 出版日期2014-5
- 单位中国科学院地质与地球物理研究所; 中国科学院大学; 中国科学院地质与地球物理研究所兰州油气资源研究中心
