Slip budgeT in subduction zones illuminated by geodetic measuRements and earthquake cycle defOrmation modelliNG – STRONG project

• Applicant: Dr. Carlos Peña
• Subject Area: Geophysics ; Geodesy, Photogrammetry, Remote Sensing, Geoinformatics, Cartography
• Term: since 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 541650676

The accumulated strain at plate boundaries (slip budget) governs the location and magnitude of large earthquakes at subduction zones, often triggering destructive tsunamis. Hence, the investigation and quantification of slip budgets are of upmost importance to improve seismic and tsunami hazard assessment. During the last years, the wealth of geophysical and geodetic observations, as well as great effort in forward and inverse modelling have allowed a better investigation of slip budgets. Despite this, it is still an open question to what extent postseismic slip as well as non-linear viscoelastic and poroelastic relaxation processes contribute to the observed surface deformation, the occurrence of aftershocks, and the slip budget estimation. This project aims at deciphering these research questions in the northern Chile subduction zone using a comprehensive workflow that integrates: 1.) Satellite geodetic and seismicity data at variable spatiotemporal scales, 2.) a state-of-the-art 4D (space and time) geomechanical forward model, and 3.) an inversion approach. Northern Chile provides a unique opportunity to investigate earthquake cycle-related deformation processes as the deformation and seismicity before, during, and after the 2014 Mw 8.1 Iquique earthquake has been successfully recorded by the multi-parameter instrumentation of the Integrated Plate Boundary Chile (IPOC). Moreover, the relatively high aridity of northern Chile results in high interferometric coherence, ideal for retrieving Interferometric Synthetic-Aperture Radar (InSAR) data with an unprecedented resolution. Specifically, this project will focus on processing and analyzing new InSAR data following the 2014 Iquique earthquake. These InSAR data will substantially improve the spatial density of Global Navigation Satellite System (GNSS) data and thus will allow constraining the model results better considering frictional fault slip, non-linear viscous relaxation, and poroelastic processes. With this quantitative information and integrated workflow, this proposal aims at 1.) Quantifying and understanding the relative contribution of the processes controlling the deformation over the seismic cycle, such as interseismic locking, postseismic slip (afterslip), non-linear viscoelastic, and poroelastic relaxation. 2.) Estimation of the present-day spatial distribution of the slip budget, which is essential to calculate the magnitude and location of future earthquakes. 3.) Elucidating the ratio between seismic and aseismic slip to the total budget. 4.) Elucidating the role of pore-pressure changes on aftershocks in space and time, particularly those occurring on-shore in the crust.

• DFG Programme: Research Grants
• Co-Investigator: Professor Bodo Bookhagen, Ph.D.