基于COMSOL Multiphysics的长白山天池多物理场耦合响应研究

Study on coupling response of multiphysical field around Tianchi lake of Changbaishan volcano based on COMSOL Multiphysics

采用COMSOL Multiphysics建立长白山天池2D多物理场模型,模拟长白山天池流场、自然电位分布及其磁场响应.研究结果表明:天池和大气降水入渗补给地下水,地下水在重力作用下向下流动时,产生电位差,形成自然电场,进而产生磁场.在火山通道外侧,电流密度方向由地表指向地下,通道周边地区磁通量密度呈现高值;在火山通道/断层破碎带内,向下运移的地下水遇到致密岩体后向上补给天池或涌出地表成泉,该过程产生向上运移的电流,电流密度方向由地下指向地表,磁通量密度呈现低值.研究长白山天池多物理场响应,有助于进一步理解长白山天池地区地下水循环过程及电磁异常出现的机理,亦可用于指导火山地区勘查、监测与开发.

2D Multiphysics field was modeled using COMSOL Multiphysics to simulate the response of flow field,self-potential and magnetic field around Tianchi lake of Changbaishan volcano.The results showed that groundwater was recharged by infiltration of the Tianchi lake and atmospheric precipitation,and the flow of groundwater driven by gravity generated the potential difference,which initiated natural electric field and the corresponding magnetic field.Outside of the volcanic channel/fault,the direction of the current density was from the surface to the underground,and the magnetic flux density was high.Inside the volcanic channel/fault,the groundwater flowed down to the rock mass then flowed upward to recharge the Tianchi lake or become hot spring,this process produced an upward current and the direction of this current density was from underground to surface,and the magnetic flux density was low.This tudy on the response characteristics of multiphysical field is helpful to further understand the process of groundwater circulation and the mechanism of electromagnetic anomalies around Tianchi lake of Changbaishan volcano,it also can be used to guide exploration,monitoring and development of the volcanic region.