EGU21-1194, updated on 09 Jan 2024
https://doi.org/10.5194/egusphere-egu21-1194
EGU General Assembly 2021
© Author(s) 2024. This work is distributed under
the Creative Commons Attribution 4.0 License.

Slip bursts during coalescence of slow slip events in Cascadia

Quentin Bletery1 and Jean-Mathieu Nocquet1,2
Quentin Bletery and Jean-Mathieu Nocquet
  • 1Université Côte d'Azur, IRD, CNRS, Observatoire de la Côte d'Azur, Géoazur, Valbonne, France
  • 2Institut de Physique du Globe de Paris, Université de Paris, CNRS, Paris, France

Both laboratory experiments and dynamic simulations suggest that earthquakes can be preceded by a precursory phase of slow slip. Observing processes leading to an acceleration or spreading of slow slip along faults is therefore key to understand the dynamics potentially leading to seismic ruptures. Here, we use continuous GPS measurements of the ground displacement to image the daily slip along the fault beneath Vancouver Island during a slow slip event in 2013. We image the coalescence of three originally distinct slow slip fronts merging together. We show that during coalescence phases lasting for 2 to 5 days, the rate of energy (moment) release significantly increases. This observation supports the view proposed by theoretical and experimental studies that the coalescence of slow slip fronts is a possible mechanism for initiating earthquakes.

How to cite: Bletery, Q. and Nocquet, J.-M.: Slip bursts during coalescence of slow slip events in Cascadia, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-1194, https://doi.org/10.5194/egusphere-egu21-1194, 2021.