关键词: 长白山天池火山, 有限元方法, 形变, 应力场

Abstract: An upper crust model is proposed,which consists of a magma reservoir and a conduit in the visco-elastic medium and is replenished from below.We solve the system as an initial value problem with a source term corresponding to the magma supply or excess pressure.The model works as follows:to supply magma to the reservoir at a given vertical velocity or give an excess pressure on the surrounding rock of the reservoir.We compared the upper crust model with Mogi model and find that the former model can not merely realize the result of Mogi model,but has a lot of advantages:it can show the different results of different reservoir shape,gets the plane stress field and section stress field and the change of stress and displacement with time.Using this model to analyze the relation in conformity with the distribution of the stress field and volcano earthquake in the area,we find that there is a very good corresponding relation.Meanwhile,we compared two models,one has background stress field only and the other has the combination of excess pressure of reservoir and background stress field,and the results show that the latter has caused the maximum shear-stress to increase gradually with time.

Key words: Changbaishan Tianchi volcano, finite-element method, deformation, stress field