Presentation by Dr. Jannes Münchmeyer
The peculiar spectrum of slow-to-fast earthquakes around the Copiapó ridge, Northern Chile
Abstract:
Subduction zones continuously accumulate stress through tectonic forcing. This stress is regularly released through (fast) earthquakes, but also through slow transient deformation, so-called slow slip events (SSEs). Understanding the slip partitioning and interaction between these fast and slow earthquakes is essential to understand how destructive megathrust events start and propagate. In this talk, I explore the spectrum of slow-to-fast earthquakes around the Copiapó ridge in Northern Chile. I present my recent results from two case studies using a dense seismo-geodetic deployment. In the first part, I discuss a shallow slow slip event in 2023, that was accompanied by a complex seismic sequence. The analysis highlights the detailed migration of the slow slip event and the underlying mechanisms. It furthermore reveals the fine-scale interface segmentation and the structural control exerted by subducted topography. In the second part, I report on results from a comprehensive search for small, slow earthquake: low-frequency earthquake (LFEs) and tectonic tremors. LFEs and tremors are commonly seen as markers of slow slip, yet these events have not been observed in Chile. Combining machine learning and classical techniques, I explore the dense seismic data set. However, while the region is rich in various, emergent seismic signals, I find no signs of LFEs or tremors. This shows that the spectrum of slow earthquakes in Northern Chile is incomplete. I end by discussing the implications of my findings on the mechanisms underlying slow and fast earthquakes and their interaction with each other.
Zoom link:
https://columbiauniversity.zoom.us/j/93219431971?pwd=b1Ctp31VJbjnz3NfhgRGaswgcNWOTV.1
