Earthquake statistics changed by typhoon-driven erosion

Philippe Steer (1) , Louise Jeandet (1) , Nadaya Cubas (2) , Odin Marc (3) , Patrick Meunier (3) , Martine Simoes (4) , Rodolphe Cattin (5) , J. Bruce H. Shyu (6) , Maxime Mouyen (7) , Wen-Tzong Liang (8) , Thomas Theunissen (9) , Shou-Hao Chiang (10) , Niels Hovius (3)

1 GR - Géosciences Rennes
2 iSTeP - Institut des Sciences de la Terre de Paris
3 GFZ - German Research Centre for Geosciences - Helmholtz-Centre Potsdam
4 IPGP (UMR_7154) - Institut de Physique du Globe de Paris
5 Géosciences Montpellier
6 NTU - National Taiwan University [Taiwan]
7 Chalmers University of Technology [Göteborg]
8 IES Sinica - Institute of Earth Sciences [Tapei]
9 UiB - University of Bergen
10 NCU - National Central University [Taiwan]

Tectonics and climate-driven surface processes govern the evolution of Earth’s surface topography. Topographic change in turn influences lithospheric deformation, but the elementary scale at which this feedback can be effective is unclear. Here we show that it operates in a single weather-driven erosion event. In 2009, typhoon Morakot delivered ~ 3 m of precipitation in southern Taiwan, causing exceptional landsliding and erosion. This event was followed by a step increase in the shallow (< 15 km depth) earthquake frequency lasting at least 2.5 years. Also, the scaling of earthquake magnitude and frequency underwent a sudden increase in the area where mass wasting was most intense. These observations suggest that the progressive removal of landslide debris by rivers from southern Taiwan has acted to increase the crustal stress rate to the extent that earthquake activity was demonstrably affected. Our study offers the first evidence of the impact of a single weather-driven erosion event on tectonics.

Domains: Sciences of the Universe [physics]; Earth Sciences; Geomorphology; Sciences of the Universe [physics]; Earth Sciences; Geophysics [physics.geo-ph]

Philippe Steer, Louise Jeandet, Nadaya Cubas, Odin Marc, Patrick Meunier, et al.. Earthquake statistics changed by typhoon-driven erosion. Scientific Reports, 2020, 10 (1), pp.10899. ⟨10.1038/s41598-020-67865-y⟩. ⟨insu-02891623⟩