Large landslide stress states calculated during extreme climatic and tectonic events on El Hierro, Canary Islands

Current stability modelling of an incipient San Andres giant landslide on El Hierro Island, Canaries, Spain _ first attempt using limited input data.

“…On the other hand, the installed monitoring system shows that the sliding masses are very sensitive to earthquake events. The slope deformation has currently an evident slow creep movement as directly observed by Klimeš et al (2016) and Blahůt et al (2017Blahůt et al ( , 2018a. Even in seismically calm periods this creep might be induced by the unconsolidated sea sediments.…”

“…For a more detailed description of the geology of the island, please refer to Blahůt et al (2018a). The characteristic three-point star morphology of El Hierro is a result of a number of enormous flank collapses ( Fig.…”

“…The broad arcuate and presumably listric fault system which defines the boundaries of the landslide mass to the northeast is terminated to the southwest by an escarpment associated with the debris avalanche at Las Playas. Geological evidence suggests that the landslide mass is moving progressively to the east and southeast (Troll and Carracedo, 2016) while creep, in the order of 0.5 mm/year, has recently been detected along its main detachment plane (Blahůt et al, 2017(Blahůt et al, , 2018a. Furthermore, the landslide mass is dissected by a series of deeply entrenched gullies, with a relative relief of more than 200 m, oriented northwest to southeast.…”

3D Dilatometer Time-Series Analysis for a Better Understanding of the Dynamics of a Giant Slow-Moving Landslide

“…The first one between 545 ka and 430 ka, and the second one between 183 ka and 52 ka [46]. Moreover, it has been proven that there is a continuous creep with a rate up to 0.5 mm•a −1 , suggesting that the landslide mass may be moving steadily to the east and southeast [32,47,48]. Numerical stability modelling [49] showed that creep movements are possible due to unconsolidated sediments at the sea bottom, and destabilization of the landslide might be possible during periods of intense seismic activity.…”

“…During this period, an offshore eruption started on 10 October 2011 and finished in March 2012 [30]. A more detailed description of the geology of the island has recently been presented elsewhere [31,32].…”