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By Sean Sullivan, Ewing-Worzel Fellowship.

Abstract:
Extensive 3D seismic data coverage exists across an area of the southeastern Caribbean margin and has been used to perform a detailed quantitative analysis of trends, geometries, and activity of recent faulting and mud volcanism in the region. Observations made can be used to deduce the extension of onshore faulting into offshore areas and the relationship or lack there of between large-scale faulting and mud volcano activity.

Preliminary observations and analysis indicate significant distinctions between the mobile mud systems in the study area. Mud volcanoes in the proximal slope (close to the modern shelf edge) appear recently active and are linear in trend. These features parallel the southwest-northeast strike-slip faults and their occurrence is associated with movement along these faults. In the far northern reaches of the study area, volcanoes are also linear in trend and are denser in number than in the rest of the study area. Here the source for the volcanoes, an extensive wall of subterranean mud provides a near surface source. These subterranean muds are being uplifted into steeply dipping, anticlinal structures cored by strike-slip faulting.

In sharp contrast to those features in the northern portions of the study area, mud volcanoes in the southern portions of the area appear less active, characterized by collapsed craters and the reworking of flows by submarine processes. Mud volcanoes in the south are associated with point-sourced vents originating along deep-seated anticlinal crests. It is possible that faulting along the crests of deep-seated anticlines provide the conduit for mobile muds to migrate through to the seafloor surface.