No abstract

This paper delineates our use of 10 708 km 2 of three-dimensional (3D) seismic data from the continental margin of Trinidad and Tobago West Indies to describe a series of mass transport complexes (MTCs) that were deposited during the Plio -Pleistocene.This area, situated along the obliquely converging boundary of the Caribbean/South American plates and proximal to the Orinoco Delta, is characterized by catastrophic shelf-margin processes, intrusive/extrusive mobile shales and active tectonism. Extensive mapping of di¡erent stratigraphic intervals of the 3D seismic survey reveals several MTCs that range in area from 11.3 to 2017 km 2 .Three types of MTCs are identi¢ed: (1) shelf-attached systems that were fed by shelf-edge deltas whose sediment input is controlled by sealevel £uctuations and sedimentation rates; (2) slope-attached systems, which occur when upperslope sediments catastrophically fail owing to gas-hydrate disruptions and/or earthquakes and (3) locally detached systems, formed when local instabilities in the sea£oor trigger relatively small collapses. Such classi¢cation of the relationship between slope mass failures and sourcing regions enables a better understanding of the nature of initiation, length of development history and petrography of such MTCs. 3D seismic enables more accurate calculation of deposit volumes, improves deposit imaging, and, thus, increases the accuracy of physical and computer simulations of mass failure processes.

No abstract

Landslides are common in aquatic settings worldwide, from lakes and coastal environments to the deep sea. Fast-moving, large-volume landslides can potentially trigger destructive tsunamis. Landslides damage and disrupt global communication links and other critical marine infrastructure. Landslide deposits act as foci for localized, but important, deep-seafloor biological communities. Under burial, landslide deposits play an important role in a successful petroleum system. While the broad importance of understanding subaqueous landslide processes is evident, a number of important scientific questions have yet to receive the needed attention. Collecting quantitative data is a critical step to addressing questions surrounding subaqueous landslides. Quantitative metrics of subaqueous landslides are routinely recorded, but which ones, and how they are defined, depends on the end-user focus. Differences in focus can inhibit communication of knowledge between communities, and complicate comparative analysis. This study outlines an approach specifically for consistent measurement of subaqueous landslide morphometrics to be used in the design of a broader, global open-source, peer-curated database. Examples from different settings illustrate how the approach can be applied, as well as the difficulties encountered when analysing different landslides and data types. Standardizing data collection for subaqueous landslides should result in more accurate geohazard predictions and resource estimation.