[S-GD03] Crustal Deformation

[SGD03-P16] Deformation of a poroelastic half-space by axisymmetric surface loads

*Yoshiya Irie¹, Shigekazu Kusumoto¹ (1.Institute for Geothermal Sciences, Kyoto University)

Water mass redistribution on the Earth's surface induces various geophysical phenomena, such as changes in the Earth's shape and gravitational field. In recent decades, Earth deformation caused by surface water loads has been studied using satellite-based geodetic techniques to quantify changes in terrestrial water storage. This quantification requires accurately modeling the solid Earth's response to surface loads, which in turn relies on appropriately assuming the Earth's rheology. However, many geodetic studies of load-induced Earth deformation on timescales of less than a few years have traditionally assumed a perfectly elastic Earth. In this study, we examine the potential effects of poroelastic behavior on Earth deformation, focusing on the differences between a poroelastic and an elastic Earth. We consider a homogeneous, isotropic, poroelastic half-space with compressible constituents and derive analytical solutions for surface displacement and gravitational potential perturbation due to both surface vertical stress and pore pressure. Our results show that the difference between the poroelastic and elastic model reaches about 30% for surface displacement and about 20% for surface gravitational potential perturbation. These findings emphasize the importance of considering poroelastic effects when analyzing Earth deformation induced by surface water loads.