Model output for the paper "Offshore landward motion shortly after a subduction earthquake implies rapid relocking of the shallow megathrust"

This repository contains the relevant data (part of numerical model output) used to plot the figures in the main body of the manuscript entitled "Offshore landward motion shortly after a subduction earthquake implies rapid relocking of the shallow megathrust", by Mario D'Acquisto and Rob Govers.

Paper abstract: "Geodetic observations after large subduction earthquakes reflect multiple postseismic processes, including megathrust relocking. What the timing of relocking is, and how well observations constrain it, is unclear. It has been inferred to explain some observed landward motion that occurs within months. It has also been considered unable to explain other, greater landward motion, including off the coast of Japan beginning weeks after the 2011 Tohoku earthquake, which is attributed to postseismic relaxation. We use generic, 3D numerical models to show that relocking, particularly of the shallow interface, is needed for postseismic relaxation to produce landward motion on the tip of the overriding plate. We argue that this finding is consistent with previous simulations that implicitly relock the megathrust where afterslip is not included, that the Tohoku megathrust thus relocked within less than two months of the earthquake, and that the shallow megathrust probably behaves as a true, unstably sliding asperity."

The model consists of a three-dimensional (3D) finite element method (FEM) simulation of the megathrust earthquake cycle with two fully elastic plates and Maxwell viscoelastic mantle.

The software used to perform the simulations and extract the model output in the files stored here was GTECTON (Govers & Wortel, 1993, 2005; Govers et al., 2018), version 2021.0. The software used to generate the relevant figures in the paper from the data was Generic Mapping Tools (GMT) (Wessel et al., 2019) version 6.4.0.

Each directory corresponds to a different model. The meaning of each model name, as well as the meaning of the file name and the internal data format of the files, are specified in the readme file (readme.txt). All files are plain text files.

For more information regarding the goals, model features, and output, please refer to the paper.

Contact person: Mario D'Acquisto - m.dacquisto@uu.nl