Impacts of Topographic Relief and Crustal Heterogeneity on Coseismic Deformation and Inversions for Fault Geometry and Slip: A Case Study of the 2015 Gorkha Earthquake in the Central Himalayan Arc

Abstract

In the past decades, space-based geodetic systems, in particular Global Positioning System (GPS) and interferometric synthetic aperture radar (InSAR), have revolutionized our ability to monitor actively deforming areas with unprecedented spatial and temporal resolutions, revealing a wide spectrum of deformation processes that related to active tectonics on Earth (Bürgmann & Thatcher, 2013). Modeling of these geodetic observations has provided further insights into the fault kinematics and rheological structure at largescale fault systems in the different stages of earthquake cycle (e.g.,

Bayesian Multi‐Model Estimation of Fault Slip Distribution for Slow Slip Events in Southwest Japan: Effects of Prior Constraints and Uncertain Underground Structure

“…This insensitivity of the elastic structure to the geodetic data does not contradict the assumption of homogeneous elastic media taken in previous studies on the same L‐SSE (Nakata et al., 2017; Ozawa et al., 2020; Seshimo & Yoshioka, 2022; Yoshioka et al., 2015). These results are also consistent with previous reports that the choice of plate boundary model often has a larger impact on the estimation results than that of the elastic structure in estimating slip distribution using geodetic data (e.g., Li & Barnhart, 2020; Lindsey & Fialko, 2013).…”

Structural controls on coseismic rupture revealed by the 2020Mw 6.0 Jiashi earthquake (Kepingtag belt, SW Tian Shan, China)

“…Without firm constraints on how rheological properties vary with depth locally, we assumed an elastic half space with standard Lamé parameters (λ and µ) of 3.2 × 10 10 Pa. We anticipate that this assumption only moderately impacts the retrieved fault parameters; for example, tests of layered and half-space elastic structures for a similar magnitude, buried earthquake in Tibet showed differences of <1 • in fault strike and dip, ∼6 • in rake, 0.2-0.5 km in fault length, top and bottom depths, and center coordinates, and 5-8% in slip and moment (Bie et al, 2014). We also assumed a flat free surface, which is appropriate given the limited (<1 km) relief across the study area and is not expected to impact the retrieved fault parameters significantly (Li & Barnhart, 2020). Finding a trade-off between slip and fault width -which is common for buried earthquakes (e.g.…”

Simultaneous Bayesian Estimation of Non‐Planar Fault Geometry and Spatially‐Variable Slip

“…The non‐planar fault in our synthetic tests is modeled within an isotropic and homogeneous elastic half‐space. More realistic earth models that consider depth‐dependent elastic parameters typically show deeper slip centroid estimates and more slip at depth compared to solutions that use a homogenous medium (Hearn & Bürgmann, 2005) and there can be considerable differences in how well the models fit observed data (Li & Barnhart, 2020; Wang & Fialko, 2018) and potential correlations between the inferred non‐planar fault geometry and the assumed earth structure. The effect of uncertain depth‐dependent elastic parameters can be included in slip estimations through model prediction error covariances (Duputel et al., 2014), which requires determination of sensitivity kernels of how model predictions change with elastic parameter modifications.…”