Abstract
AbstractThe parameters allowing for near-trench megathrust ruptures are debated and commonly involve the presence of site-dependent tectonic factors (e.g. rough subducting topography, amount of sediments), implying the need for direct geophysical observations. Here we use seismic imaging techniques to explore the mechanisms triggering shallow ruptures in the Rivera subduction zone, along the non-accretionary Jalisco-Colima continental margin, W Mexico, where three large (Mw~8) tsunamigenic megathrust earthquakes occurred in the last century. The seismic image reveals large interplate topographic variations morphologically alike to incoming trench-parallel ridges seaward of the study area. Ridge subduction only occurs along the southern non-accretionary margin of the Rivera system, where past earthquakes released large near-trench coseismic energy, indicating that subducting ridges enhance interplate coupling. Subducting ridges uplift the margin, causing upper-plate fracturing and low rigidity areas. Such elastic structure quantitatively explains the dynamics of slow and tsunamigenic ruptures in the past. We conclude that ridge subduction beneath the Jalisco-Colima continental margin promotes shallow seismogenesis and explains the large tsunamigenic potential of the area.
Funder
Departament d’Innovació, Universitats i Empresa, Generalitat de Catalunya
Universidad Nacional Autónoma de México
Consejo Nacional de Ciencia y Tecnología
Publisher
Springer Science and Business Media LLC
Subject
General Earth and Planetary Sciences,General Environmental Science
Reference50 articles.
1. McIntosh, K. D. et al. In The Seismogenic Zone of Subduction Thrust Faults: Part III (eds Dixon, T. H. & Moore, J. C.) Ch. 9 (Columbia Univ. Press, 2007).
2. Sallarès, V. et al. Overriding plate structure of the Nicaragua convergent margin: relationship to the seismogenic zone of the 1992 tsunami earthquake. Geochem. Geophys. Geosyst. 14, 3436–3461 (2013).
3. Polet, J. & Kanamori, H. Shallow subduction zone earthquakes and their tsunamigenic potential. Geophys. J. Int. 142, 684–702 (2000).
4. Bell, R. et al. Hikurangi margin tsunami earthquake generated by slow seismic rupture over a subducted seamount. Earth Planet. Sci. Lett. 397, 1–9 (2014).
5. Geersen, J. Sediment-starved trenches and rough subducting plates are conducive to tsunami earthquakes. Tectonophysics 762, 28–44 (2019).
Cited by
1 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献