Slow Slip Event detection through InSAR and GNSS time series

Project Description :

At subduction zones, tectonic plates continuously converge and become mechanically coupled, leading to the progressive accumulation of elastic strain that is episodically released by large earthquakes. Yet, part of this energy can also be released aseismically, through Slow Slip Events (SSEs)—transient episodes of fault slip that occur over days to months, without generating strong seismic waves.

Understanding the physics and occurrence of SSEs is essential, as these phenomena sometimes precede or interact with large earthquakes, revealing how stress is transferred along the megathrust. By identifying where and when SSEs occur, we can gain insight into the stress distribution, rheological properties, and frictional behavior of the plate interface.

This project will focus on the characterization of SSE activity in Central Chile, near Los Vilos, an area located at the southern edge of the 2015 Illapel earthquake rupture zone. This region has experienced persistent afterslip and recurrent seismic swarms, suggesting a complex interplay between seismic and aseismic slip.

The work will combine continuous GNSS time series and InSAR data to detect and analyze slow slip transients. The methodological framework will include :

Pre-processing and cleaning of geodetic time series to remove noise and non-tectonic signals.
Signal decomposition using methods such as Independent Component Analysis (ICA) or Principal Component Analysis (PCA) to isolate transient deformation modes.
Geodetic inversion of the GNSS and InSAR displacement fields to infer the spatial distribution of slip on the subduction interface.

By integrating these datasets and techniques, the project aims to identify the spatiotemporal evolution of SSEs, assess their possible relation to seismic swarm activity, and provide new constraints on the mechanical segmentation of the Chilean subduction zone.

Mis à jour le 6 novembre 2025