CATASTROPHIC COLLAPSE OF THE VOLCANIC ISLAND OF HIERRO 15 KA AGO AND THE HISTORY OF LANDSLIDES IN THE CANARY ISLANDS

摘要

Landslides play an important role in the evolution of many volcanic islands, producing huge fields of blocky volcanic debris on their submarine slopes. Sidescan sonar images presented in this paper provide evidence for a large debris avalanche, El Golfo, on the northern flank of Hierro Island in the Canary Islands. Angular blocks, as much as 1.2 km across and 200 m high, cover the debris avalanche surface. El Golfo avalanche is related to both the Canary debris how and a volcaniclastic turbidite found in the Madeira abyssal plain 600 km west of the Canaries. Dating of the turbidite and the failure scarp onshore indicates that the failure probably occurred between 13 and 17 ka. There appears to be a general correlation between volcaniclastic turbidites in the abyssal-plain sequence and landslides in the Canaries during the past 750 ka. Tentatively, this correlation suggests that seven major landslides have affected the Canaries in that time. [References: 26]