Bartomeu Dader i Pericàs as eyewitness and chronicler of the Es Marroigs landslide in 1924 (Majorca). Analysis from current knowledge

Abstract

The Es Marroigs landslide (Fornalutx, Majorca), which started on the 16 December 1924, is one of the largest mass-movement events historically registered on the island of Majorca. A complex planar-landslide debris flow was triggered, which affected a cultivated area of 73 400 m², on the northern slope of the Bonnàber mountain range after persistent rain. The retrogression and subsidence of the head of the landslide caused the undermining of a talus-scree, with a volume of rock blocks of around 50 000 m³, which suddenly invaded and moved long distances over the landslide surface (over 300 m). The complex slide, with a final runout of 600 m, involved a displaced mass of 625 000 m³ in volume, buried several farmhouses in the area and caused economic losses valued at 200 000 pesetas of that time. The geologist Bartomeu Darder (1894-1944) was one of the eyewitnesses of the landslide. His testimony, observations and conclusions were published in the newspapers a few days later, reporting one of the first press notices in this field. One year later, Darder published a scientific manuscript in the Royal Spanish Bulletin of Natural History, with two relevant photos, one of them capturing the landslide in action. The present work analyses, from current knowledge, the Es Marroigs land-slide: type of failure, evolution, characteristics, the impact, the triggering conditions etc., and also takes into account the thorough descriptions carried out by Darder.