A 3D finite-element mesh for modeling large-scale surface deformation induced by subduction megathrust earthquakes: Application to Chile

Hugo Boulze¹, Jean-Didier Garaud², Emilie Klein¹, Luce Fleitout¹, Christophe Vigny¹ and Vincent Chiaruttini²

¹ Laboratoire de Géologie, CNRS - Ecole normale supérieure - PSL University, Paris, France

² DMAS, ONERA, Université Paris-Saclay, 92320, Châtillon, France

Contacts : boulze@geologie.ens.fr, jean-didier.garaud@onera.fr

How to cite : Please, when using Chile_Mesh_v1.0 or any content from this work cite: "A 3D finite-element mesh for modeling large-scale surface deformation induced by subduction megathrust earthquakes: Application to Chile" (2025) Hugo Boulze, Jean-Didier Garaud, Emilie Klein, Luce Fleitout, Christophe Vigny, Vincent Chiaruttini, submitted to Seismica.

Licenses : All files within this repository are distributed under either the GNU GPL-v3 license or CC BY-NC-SA 4.0:

• Mesh files Chile_Mesh_v1.0 (.geof, .inp, .gmsh) by Hugo Boulze are licensed under CC BY-NC-SA 4.0
• Program files (*.py) are licensed under the GNU GPL-v3
• Data files (*.inp, *.dat, *.csv, *.mast, images) are licensed under CC BY-NC-SA 4.0
• If a specific file explicitly states an alternate licensing terms, those terms shall supersede the default GPL-v3 license for that particular file.

Geophysical zones included in Chile_Mesh_v1.0

2D sketch representing the geophysical zones included in chile-mesh_v1.0. CH: channel. AP: Accretionary prism. The fault-plane extends from -6 km to -70 km depth. The node-split technique of the fault plane (Melosh et Raefsky, 1981) gives two groups of nodes: fault plane A and fault plane B, respectively oriented towards the Earth's center and the surface. The depth of zones is indicated as an italic number.

Mesh construction

STEP 1: Creation of a .csv file containing the coordinates (lon, lat, depth) of the surface of the slab based on Slab2.0 (Hayes et al. 2018)

STEP 2: Creation of the subduction interface. First, the 2D slice of the interface is drawn. Then, it is extended to 3D along the path of the subduction trench.

STEP 3: The slab is deformed according to the surface of Slab2.0.

STEP 4: The subduction mesh is inserted in the mesh box using Zcracks.

STEP 5: The planes at a given depth (e.g. -70km, -200km) are created by knifing the mesh.

STEP 6: The elsets (e.g. LITHOSPHERE, ASTHENOSPHERE) are finally created. The mesh is refined.

Finite Element Analysis

The FEA directory provides examples using Chile_Mesh_v1.0 with Zset/Zebulon.

Prerequisites

The script check_prerequisites.sh verifies some software prerequisites.

The pipeline works successfully with:

• Zset, using a development version svn:23164.
• GMT, version 6.3.0.
• MMG, version 5.7.3.