Analysis of tectonic and magmatic stresses controlling volcanic spreading over multiple time scales. A case study from Kilauea Volcano, Hawaii, USA

火山扩张定义了火山两侧沿着火山堆下方的近水平结构向外位移，并已在世界范围内观察到。这些运动的原因并不总是很清楚。有些火山的变形速率比重力作用下预期的要高，并讨论了岩浆应力的作用。在这项研究中，我们建议使用夏威夷的基拉韦厄火山，通过数值模拟来研究扩张火山的动力学。特别是，将模拟可能导致火山侧翼运动和/或影响侧翼应力状态的各种力（重力、孔隙弹性力、岩浆超压以及导致静态应力变化和瞬态应力的幕式构造和岩浆变形事件）产生的应力和应变场随时间的演变。将测试对模型参数（如材料特性和断层摩擦）的不同假设。为了将模型结果与观测结果进行比较，我们将使用来自全球定位系统、干涉卫星孔径雷达和地面大地测量的时间序列的表面速度数据。这一预期成果将有助于更好地了解火山扩张以及构造应力和岩浆应力在长、短时间尺度上的相互作用。

Volcanic spreading defines the outward displacement of flanks of a volcano along subhorizontal structures beneath the volcanic pile and has been observed worldwide. The cause of these motions is not always well understood. Some volcanoes show higher deformation rates than expected from gravity body force and the role of magmatic stresses has been discussed. In this study we suggest to use Kilauea Volcano, Hawaii to investigate the dynamics of spreading volcanoes through numerical modeling. In particular the time-dependent evolution of stress and strain fields resulting from various forces potentially causing volcanic flank motions and/or influencing the stress state at the flank (gravity body force, poro-elastic forces, magmatic overpressures, and episodic tectonic and magmatic deformation events causing static stress change and transient stresses) will be simulated. Different assumptions on model parameters such as material properties and fault friction will be tested. To compare model results to observations we will use surface velocity data from time-series of Global Positioning System, Interferometric Satellite Aperture Radar, and ground geodesy will be used. This expected outcome will provide a better understanding of volcanic spreading and the interaction of tectonic and magmatic stresses over long- and short time scales.