5:15 PM - 7:15 PM
[SVC33-P10] Numerical simulation analysis of crust subsidence during the magma intrusion process
Keywords:Caldera, Magma, Numerical simulation, Physics of the Earth's Interior
Surface subsidence on Earth is closely related to volcanic activity and crustal deformation, and understanding its mechanisms is essential for elucidating the dynamics of the Earth's interior. In this study, we conducted two-dimensional numerical simulations to investigate the mechanisms of crust subsidence during the magma intrusion process. Specifically, we focused on the effects of (1) the initial magma temperature, (2) the temperature of the Mohorovičić discontinuity (Moho), and (3) the presence of molten material on the subsidence process, and analyzed the dynamics of crustal deformation and subsidence in detail.
The simulation results indicated that when the initial magma temperature was set below 1600 K, intrusion occurred but no significant crust subsidence was observed. In contrast, when the initial temperature was set above 1700 K, subsidence occurred following magma intrusion and cooling. During this process, the velocity vector within the crust increased in the negative y-direction (vertically downward direction). This suggests that the cooling and solidification of the intruded magma led to an increase in density, generating compressive stress that promoted subsidence. Furthermore, as subsidence progressed, a ring-like arrangement fault structure was observed in the upper middle crust. The study also provided significant insights into the influence of the Moho temperature. When the Moho temperature was low, the temperature difference between the magma and the surrounding crust was greater, slowing the cooling rate and causing the intruded rock to rise within the crust, forming a more dome-shaped structure. Conversely, when the Moho temperature was high, the smaller temperature difference caused the intruded rock to spread more horizontally, resulting in broader subsidence. The analysis of strain rate revealed that differences in temperature conditions significantly affected the mode of crust deformation. Additionally, considering the presence of molten material, the study demonstrated that buoyancy played a crucial role in the subsidence process. As the proportion of molten material increased, the density of the intruded magma decreased, leading to stronger buoyancy effects, which altered the direction and magnitude of the velocity vectors. In particular, when the proportion of molten material exceeded 20%, the rate of subsidence slowed, but the overall amount of subsidence increased. Furthermore, localized divergence of the velocity vectors was observed in the subsidence region, indicating that crust deformation associated with subsidence progressed more heterogeneously. The findings of this study are applicable to the simulation of caldera formation and crustal deformation, contribute to a deeper understanding of subsidence processes in volcanic activity. Notably, the strain rate vector and the velocity vector analysis confirmed that changes in the stress field due to the cooling and solidification of magma were the primary driving forces of subsidence. The approach taken in this study has the potential to contribute to improvements in volcanic activity prediction and crustal deformation modeling.
The simulation results indicated that when the initial magma temperature was set below 1600 K, intrusion occurred but no significant crust subsidence was observed. In contrast, when the initial temperature was set above 1700 K, subsidence occurred following magma intrusion and cooling. During this process, the velocity vector within the crust increased in the negative y-direction (vertically downward direction). This suggests that the cooling and solidification of the intruded magma led to an increase in density, generating compressive stress that promoted subsidence. Furthermore, as subsidence progressed, a ring-like arrangement fault structure was observed in the upper middle crust. The study also provided significant insights into the influence of the Moho temperature. When the Moho temperature was low, the temperature difference between the magma and the surrounding crust was greater, slowing the cooling rate and causing the intruded rock to rise within the crust, forming a more dome-shaped structure. Conversely, when the Moho temperature was high, the smaller temperature difference caused the intruded rock to spread more horizontally, resulting in broader subsidence. The analysis of strain rate revealed that differences in temperature conditions significantly affected the mode of crust deformation. Additionally, considering the presence of molten material, the study demonstrated that buoyancy played a crucial role in the subsidence process. As the proportion of molten material increased, the density of the intruded magma decreased, leading to stronger buoyancy effects, which altered the direction and magnitude of the velocity vectors. In particular, when the proportion of molten material exceeded 20%, the rate of subsidence slowed, but the overall amount of subsidence increased. Furthermore, localized divergence of the velocity vectors was observed in the subsidence region, indicating that crust deformation associated with subsidence progressed more heterogeneously. The findings of this study are applicable to the simulation of caldera formation and crustal deformation, contribute to a deeper understanding of subsidence processes in volcanic activity. Notably, the strain rate vector and the velocity vector analysis confirmed that changes in the stress field due to the cooling and solidification of magma were the primary driving forces of subsidence. The approach taken in this study has the potential to contribute to improvements in volcanic activity prediction and crustal deformation modeling.