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

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 km 3 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.

Long‐term (17 Ma) turbidite record of the timing and frequency of large flank collapses of the Canary Islands

“…It has been proposed that several landslides were initiated from the Teno Massif between 6.3 and 6.0 Ma, and these were responsible for both the onshore unconformities above the Masca Formation and an offshore debris avalanche (Table ) [ Walter and Schmincke ; Masson et al ., ; Acosta et al ., ; Leonhardt and Soffel , ; Longpré et al ., ]. The Anaga Massif collapsed at 4.7‐4.1 Ma (Table ) [ Masson et al ., ; Acosta et al ., ; Llanes et al ., ; Walter et al ., ]. The Tigaiga debris avalanche is another failure from the northern flank of Tenerife (Table ), which has been tentatively dated at >2.3 Ma [ Cantagrel et al ., ; Krastel et al ., ; Acosta et al ., ].…”

Validación del método de predicción de direcciones principales de drenaje subterráneo en macizos anisótropos, en los terrenos volcánicos del macizo de Anaga, Tenerife

“…Los aluviones o depósitos de barranco: se caracterizan por presentar una relativamente buena clasificación, un mayor grado de redondeamiento de los clastos y una estratificación más definida (Criado, C., A. Yanes, 1981;Llanes, P., Muñoz, A. et al, 2004).…”