The most recent megalandslides of the Canary Islands: El Golfo debris avalanche and Canary debris flow, west El Hierro Island

Abstract

Abstract. Two major landsliding events have been identified west of the island of E1 Hierro: The E1 Golfo debris avalanche and the Canary debris flow. These landslides were identified from swath bathymetry, seismic reflection, and TOpographic PArametric Sonar (TOPAS) data obtained in December 1994 during a cruise on board the Spanish R/V Hesperides. The E1 Golfo debris avalanche originated subaerially on the western flank of the island of E1 Hierro and has an associated 150 km 3 rock debris deposit on the base of slope. The Canary debris flow, which dislocated some 400 km 3 of sediment, resulted from a different failure originated between 3200 and 3700 m depth at the base of slope of the island of E1 Hierro. According to the studied data set, its source area seems to have been covered by the E1 Golfo debris avalanche deposit. The triggering of the E1 Golfo debris avalanche (between 136 and 21 ka) is related to tensional stresses on the rift zones of the island. These rift zones control the emplacement and morphology of the landslide scar. In the Canary Islands, a relation between landslide ages and island ages can be established, indicating a link between subsidence history, age of shield phases, and giant landslides.

La erupción submarina de La Restinga en la isla de El Hierro, Canarias: Octubre 2011-Marzo 2012

“…1B), que parece pertenecer a un edificio volcánico más antiguo, al igual que el monte submarino Henry, situado al SE, ambos cubiertos por varios metros de sedimentos (Mitchell, 1993). En campañas oceanográficas en zonas próximas (<3 km de distancia) a la localización de la actual erupción de 2011-12, se dragaron numerosas muestras de lavas (picritas y basaltos alcalinos) e hialoclastitas con escaso grado de alteración, lo que evidencian una edad muy reciente (Mitchell, 1993;Urgeles et al, 1997Urgeles et al, , 1998Schmincke et al, 1998;Gee et al, 1999;Ye et al, 1999;Schmincke & Graf, 2000;Krastel & Schmincke, 2002;Masson et al, 2002).…”

Flank stability and processes off the western Canary Islands: a review from El Hierro and La Palma

“…Three large debris avalanches appear to have occurred on the island of El Hierro: El Golfo, on the northwest flank, El Julán, on the southwest flank, and Las Playas, on the southeast flank. El Golfo covers 2,600 km 2 of the sea-floor and involves 180 km 3 of mobilized debris (Urgeles et al, 1997), El Julán covers 900 km 2 and is 100 km 3 in volume (Holcomb and Searle, 1991). The western flank of La Palma is affected by up to four debris avalanches, giving an overall volume of 750 km 3 (Urgeles et al, 1999b).…”

“…Several debris avalanches involving large volumes of volcaniclastic material have recently been discovered on the submarine slopes of the Canary Islands (Watts andMasson, 1995, 1998;Masson, 1996;Urgeles et al, 1997Urgeles et al, , 1999bFunck and Schminke, 1998) (Fig. 1).…”

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

“…The origin of the steep escarpments bounding the seawardfacing embayment in the Canaries has been the subject of different interpretations, since its first association with gravitational processes by Bravo (1952). Nowadays it is accepted that giant landslides are a common feature in the Canary Islands and the relation between giant landslides and straight-walled valleys, calderas and wide coastal embayments, has been found onshore (Ancochea et al, 1990;Ancochea et al, 1994;Carracedo 1994;Guillou et al, 1996) and offshore (Watts and Masson, 1995;Teide Group, 1997;Masson, 1996;Urgeles et al, 1997;Carracedo, 1999Mitchell et al, 2003, Masson et al, 2002 andAcosta et al, this issue). In Figure 7 the geographical position of the onshore Güimar's Valley scarp has been plotted, as well as the trace of the scarp found offshore.…”

“…In the recent past, it appears that Tenerife, together with El Hierro and La Palma, has been the most active of the Canary Islands, in terms of both volcanic and landslide activity (Urgeles et al, 1997). Such voluminous Quaternary volcanic activity was focussed on the island's centre (Cañadas Volcano, 1.9-0.2 Ma) and on a chain of basaltic eruption centres spreading from the central volcano to the northeast (Cordillera Dorsal, peak activity, 0.8 Ma) (Ancochea et al, 1990).…”