EGU23-5874, updated on 09 Jan 2024
https://doi.org/10.5194/egusphere-egu23-5874
EGU General Assembly 2023
© Author(s) 2024. This work is distributed under
the Creative Commons Attribution 4.0 License.

Geodetic evidence that earthquakes start with precursory slip

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, Geoazur, Sophia Antipolis, France (bletery@geoazur.unice.fr)
  • 2Institut de Physique du Globe de Paris, Université de Paris, CNRS, Paris, France (nocquet@geaozur.unice.fr)

The existence of a potentially observable precursory phase of slip on the fault before large earthquakes has been debated for decades. Though observations preceding a handful of large events have been proposed as possible indicators of precursory slip, these observations do not directly precede the earthquakes, are not seen before most events and are commonly observed without being followed by earthquakes. Here we present a global analysis of geodetic measurements prior to large earthquakes, based on high-rate time series recorded before 78 large (Magnitude ≥ 7) seismic events. Our analysis highlights a 2 hour-long exponential signal consistent with acceleration of precursory slip on the fault. Our observation indicates that precursory phases of slip exist and that future improvements in measurement precision could allow to monitor them, making earthquake prediction potentially achievable.

How to cite: Bletery, Q. and Nocquet, J.-M.: Geodetic evidence that earthquakes start with precursory slip, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-5874, https://doi.org/10.5194/egusphere-egu23-5874, 2023.