Trench-parallel ridge subduction controls upper-plate structure and shallow megathrust seismogenesis along the Jalisco-Colima margin, Mexico
Por:
Prada, Manel, Bartolome, Rafael, Gras, Claudia, Bandy, William L., Dañobeitia J.J.
Publicada:
1 ene 2023
Resumen:
The 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. © 2023, The Author(s).
Filiaciones:
Prada, Manel:
Barcelona Center for Subsurface Imaging, Institut de Ciencies del Mar (ICM), CSIC, Barcelona, Spain
CSIC, ICM, Barcelona Ctr Subsurface Imaging, Barcelona, Spain
Bartolome, Rafael:
Barcelona Center for Subsurface Imaging, Institut de Ciencies del Mar (ICM), CSIC, Barcelona, Spain
CSIC, ICM, Barcelona Ctr Subsurface Imaging, Barcelona, Spain
Gras, Claudia:
Barcelona Center for Subsurface Imaging, Institut de Ciencies del Mar (ICM), CSIC, Barcelona, Spain
Now at Frontwave Imaging S.L, Barcelona, Spain
CSIC, ICM, Barcelona Ctr Subsurface Imaging, Barcelona, Spain
Now Frontwave Imaging SL, Barcelona, Spain
Bandy, William L.:
Instituto de Geofísica, Universidad Nacional Autónoma de México, México D.F., Mexico
Univ Nacl Autonoma Mexico, Inst Geofis, Mexico City, Mexico
Dañobeitia J.J.:
European Multidisciplinary Seafloor and water column Observatory, European Research Infrastructure Consortium, Rome, Italy
European Res Infrastruct Consortium, European Multidisciplinary Seafloor & water colum, Rome, Italy
gold
|