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Morphological and structural analysis in the Anaga offshore massif, Canary Islands: fractures and debris avalanches relationships

Llanes Estrada, Pilar and Muñoz, Araceli and Muñoz Martín, Alfonso and Acosta, Juan and Herranz, Pedro and Carbó Gorosabel, Andrés and Palomo, Carlos (2003) Morphological and structural analysis in the Anaga offshore massif, Canary Islands: fractures and debris avalanches relationships. Marine Geophysical Researches, 24 . pp. 91-112. ISSN 00253235

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Abstract

As part of the ‘National Hydrographic and Oceanographic Research Plan for the Spanish Exclusive Economic
Zone’, multibeam bathymetry and seismic reflection profiles were obtained in the Canary Islands aboard the R/V
Hespérides. The submarine flanks of the Anaga offshore extension of Tenerife Island are here studied to analyze its
geomorphology. In the north sector of the Anaga submarine massif, the extension of the Anaga Debris Avalanche
has been mapped for the first time, and a volume of 36 km3 was calculated. The relationship between the Anaga
and Orotava Debris Avalanches is also described. Faulting has been recognized as a key process for the occurrence
of debris avalanches and the growth of volcanic lineaments. Moreover, faulting affects previous structures and the
channelling of debris flows. Structural analysis shows the typical radial pattern of an oceanic island. In addition, a
NE-SW dominant direction of faulting was obtained, consistent with the Tenerife Island structural trend seen in the
Anaga Massif and Cordillera Dorsal. NW-SE and E-W are two other main trends seen in the area. Special interest
is manifest in two long faults: ‘Santa Cruz Fault’ bounds the southern edge of Anaga offshore Massif with a length
of 50 km and a direction that changes from NE-SW to almost E-W. The Güimar Debris Avalanche was probably
channeled by this fault. The ‘Guayotá Fault’ was recognized in several seismic profiles with a N-S direction that
changes towards NW-SE at its southern end. This fault affects the more recent sediments with a vertical offset of
25–30 m, along 60 km. It has been interpreted as a transpressive strike-slip fault.

Item Type:Article
Uncontrolled Keywords:Anaga massif; Bathymetry; Debris avalanche; Fractures; Tenerife island
Subjects:Sciences > Geology > Geodynamics
ID Code:5963
Deposited On:21 Nov 2006
Last Modified:06 Feb 2014 07:46

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