EGU2020-10429
https://doi.org/10.5194/egusphere-egu2020-10429
EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Rupture characteristics of the 2019 North Peru intraslab earthquake (Mw8.0)

Martin Vallée1, Raphaël Grandin1, Jean-Mathieu Nocquet2, Juan-Carlos Villegas3, Sandro Vaca4, Yuqing Xie5, Lingseng Meng5, Jean-Paul Ampuero2, Patricia Mothes4, and Paul Jarrin2,6
Martin Vallée et al.
  • 1Université de Paris, Institut de physique du globe de Paris, CNRS, IGN, F-75005 Paris, France (vallee@ipgp.fr)
  • 2Géoazur, IRD, Université de Nice Sophia-Antipolis, Observatoire de la Côte d’Azur, CNRS, Valbonne, France
  • 3Instituto Geofísico del Perú, Lima, Perú
  • 4Instituto Geofísico-Escuela Politécnica Nacional, Quito, Ecuador
  • 5School of Earth, Planetary and Space Sciences, University of California, Los Angeles, USA
  • 6Institut des Sciences de la Terre de Paris, CNRS UMR 7193, Sorbonne Université, Paris, France

According to GlobalCMT, the 2019/05/26 North Peru earthquake is the largest event since 1976 in the wide depth range between 70km and 550km. Its hypocentral location (at about 130km depth) inside the Nazca slab geometry, together with its normal focal mechanism, favor an origin related to slab bending. Owing to its magnitude and depth, this earthquake generated large coseismic displacements over a broad area, that were geodetically measured by InSAR and GNSS. By combining these observations with regional and teleseismic data, we invert for the rupture process of the event, and first focus on the actual focal plane. Inversion reveals that the steeper plane (dipping 55-60° to the East) is preferred. A clear northward propagation is also imaged, with rupture traveling ~200km in 60s, and with little extent in the dip direction. This narrow rupture aspect implies that the stress drop is significant, even if a simple duration-based measurement would not indicate so. These inversion results obtained at relatively low frequency (below 0.2Hz) are then thoroughly compared with back-propagation images obtained at higher frequency (at 0.5-4Hz), which also highlight the dominantly northward rupture propagation with an average rupture speed of about 3 km/s. Implication in terms of earthquake rupture dynamics and occurrence of such large intermediate depth earthquakes in slabs will finally be discussed.
    

How to cite: Vallée, M., Grandin, R., Nocquet, J.-M., Villegas, J.-C., Vaca, S., Xie, Y., Meng, L., Ampuero, J.-P., Mothes, P., and Jarrin, P.: Rupture characteristics of the 2019 North Peru intraslab earthquake (Mw8.0), EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-10429, https://doi.org/10.5194/egusphere-egu2020-10429, 2020

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