Title

Investigation of mass wasting on the continental slope and rise

Document Type

Conference Proceeding

Date of Original Version

1-30-2004

Abstract

A methodology is presented for the investigation of submarine slope instability. This approach integrates the results of a variety of tools and methods, including multibeam, side scan and subbottom acoustic data, geotechnical sampling and testing, and advanced dating techniques. For slides/slumps that have the potential for causing tsunamis, the use of long, large-diameter piston corers is a cost-effective way of obtaining good quality sediment samples. Using a Multi-Sensor Core Logger and geotechnical analyses, a baseline of sediment properties is developed from nearby stable, unfailed regions, which is then compared to more active areas where faulting and instability is suspected. Clear evidence of past and recent slope failures can often be obtained from the stress history of the sediment derived from consolidation test results and from careful identification of naturally deposited sediments overlying relic failures. This methodology was applied for the investigation of slope failures along a study corridor in deepwater Gulf of Mexico. Large failures were identified from multibeam data, and coring locations were chosen based on subbottom and side scan data obtained with a deep-tow system. Buried failures were identified from detailed bulk density measurements, geotechnical test results, and paleomagnetic and 14C dating techniques. Dating of these failures can provide information regarding the triggering mechanisms of these events, which can be used to assess the current risk of new instabilities. © 2003 Elsevier B.V. All rights reserved.

Publication Title

Marine Geology

Volume

203

Issue

3-4

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