Geohazard from submarine landslides in the Mediterranean Sea: a basin approach
Presented by Dr. Roger URGELES on 23 Sep 2013 from 17:15 to 19:15
Type: Poster presentation
Session: Poster session
Submarine landslides are ubiquitous along Mediterranean continental margins. With the aim to understand mass wasting processes and related hazard at the scale of a large marine basin encompassing multiple geological settings, we have compiled data on their geometry, age, and trigger mechanism with a geographic information system. The distribution of submarine landslides in the Mediterranean reveals that major deltaic wedges have a higher density of large submarine landslides, while tectonically active margins are characterized by relatively small failures. In all areas landslide size distributions display power-law scaling for landslides > 1 km3. We find consistent differences on the exponent of the power-law (θ) depending on the tectonic setting. Available age information suggests that failures exceeding 1000 km3 are infrequent and may recur every ~40 kyr. Smaller failures that can still cause significant damage might be relatively frequent (failures > 1 km3 may recur every 40 years). The database highlights that our knowledge of submarine landslide activity with time is limited to a few tens of thousands of years. Available data suggest that submarine landslides may preferentially occur during lowstand periods, but no firm conclusion can be made on this respect, as only 70 landslides (out of 696 in the database) have relatively accurate age determinations. The temporal pattern and changes in frequency magnitude distribution suggest that sedimentation patterns and pore pressure development have had a major role in triggering slope failures and control the sediment flux from mass-wasting to the deep basin.