岩浆活动与构造应力的相互作用及其与火山活动状态的关系

Volcano-tectonic interaction and the relation with the state of volcanic activity

本文考虑一个包含岩浆囊和火山隆起的三维黏弹性地壳有限元模型,通过数值模拟的方法揭示了岩浆活动与构造应力之间的相互作用.首先,在底部岩浆的持续补给作用下,总结了火山地表形变、应力大小和岩浆囊过剩压力在岩浆补给不同状态下的特征和表象;同时本文研究了构造应力场变化对火山岩浆囊应力的影响,发现10 MPa的板块应力作用能够引起岩浆囊内±1.2～1.6 MPa的压力变化,这个基级足以对岩浆囊形成扰动,从而引发各种火山活动.

We develop a three-dimensional viscoelastic model including a magma chamber and an extrusive volcano to show that there is a volcano-tectonic interaction by finite element numerical simulation method. First, we sum up the character of surface deformation, stress distribution, and super pressure in magma chamber with the magma supplying in different state. Then, we analyse the effect of tectonic stress field change on magma chamber. The results show that offerring 10 MPa stress boundary condition can bring ±1.2-1.6 MPa change of super pressure in magma chamber. This order of magnitude can trigger the unrest in volcanic systems, and then induce volcanic activities.