Volcanic edifice slip events recorded on the fault plane of the San Andres Landslide, El Hierro, Canary Islands

0532845 - ÚSMH 2021 RIV NL eng J - Journal Article
Blahůt, Jan - Mitrovic-Woodell, I. - Baroň, Ivo - René, Miloš - Rowberry, Matthew David - Blard, P.H. - Hartvich, Filip - Balek, Jan - Meletlidis, S.
Volcanic edifice slip events recorded on the fault plane of the San Andres Landslide, El Hierro, Canary Islands.
Tectonophysics. Roč. 776, FEB 5 (2020), č. článku 228317. ISSN 0040-1951. E-ISSN 1879-3266
R&D Projects: GA ČR(CZ) GJ16-12227Y
Institutional support: RVO:67985891
Keywords : Volcanic collapse * Frictionite * Cataclasis metamorphism * Silica layer * Cosmogenic radionuclide dating * Canary Islands
OECD category: Geology
Impact factor: 3.933, year: 2020
Method of publishing: Limited access
https://reader.elsevier.com/reader/sd/pii/S0040195119304329?token=EB9FC3E42D12336F3D353B5BFD480A4E1C3B6E69E7CE5BAB0E5C5D475C037B5DD598D5ED76DF16198117E117519B765C

Volcanic flank collapses often result in giant debris avalanches that are capable of travelling tens of kilometres across the ocean floor and generating tsunamis that devastate distant communities. The San Andres Landslide on El Hierro, Canary Islands, represents one of the few places in the world where it is possible to investigate the landslide mass and fault planes of a volcanic collapse structure. In this study, a new conceptual model for the development of this enormous slump is presented on the basis of structural geological and geomorphological measurements, petrological and microstructural analyses, and cosmogenic radionuclide dating. Structural geological and geomorphological measurements indicate that the fault plane records two distinct events. Petrological and microstructural analyses demonstrate that a thin layer of frictionite covers the surface of the fault in contact with an oxidised tectonic breccia that transitions into the underlying undeformed basanite host rock. This frictionite comprises a heterogeneous cataclastic layer and a translucent silica layer that are interpreted to represent two separate slip events on the basis of their architecture and crosscutting relationships. Cosmogenic He-3 dating reveals a maximum exposure age of 183 +/- 17 ka to 52 +/- 17 ka. Arguments are presented in support of the idea that the first slip event took place between 545 ka and 430 ka, prior to significant clockwise rotation of El Hierro, and the second slip event took place between 183 ka and 52 ka, perhaps in association with one of the giant debris avalanches that occurred around that time. This is the first time that more than one slip event has been recognised from the fault plane of the San Andres Landslide. It is also believed to be the first time a silica layer resulting from frictional melt has been described in a volcanic setting.
Permanent Link: http://hdl.handle.net/11104/0311247