Craig Shipp

Studying geohazards with ocean cores. Addressing geologic hazards through ocean drilling: An IODP international workshop, Portland, Oregon, 27–30 August 2007

How can Integrated Ocean Drilling Program (IODP) drilling contribute to the understanding of highly hazardous geologic events, such as great earthquakes, submarine landslides, and volcano collapses, all of which can generate devastating tsunamis and threaten huge parts of Earths coasts? Eighty-nine participants from 18 countries grappled with this topic for 4 days near Portland, Oreg., in late August and spawned a number of working groups focused on generating proposals to gain such understanding. Ideas included potential scientific targets and locations for drilling, proposed observatories to study active and potentially precursory processes, in situ measurement techniques, and methodologies for interpreting sedimentary records. A common theme was the unique opportunity afforded by IODP drilling to study active processes relevant to geohazards, especially at known points within the deformation cycle. The meeting also led to proposed additions to the IODP initial science plan.

Controls on the Seismic Espression of Gas Hydrates in Marine Settings

The presence of gas hydrates in natural environments was originally inferred thanks to the identification of a bottom simulating reflector (BSR), representing the base of the gas hydrate stability zone (BGHSZ). Even if the stability condition necessary to allow hydrates formation are present in a huge portion of ocean sediments, their distribution in the sedimentary basins appear to be patchy, even at the seismic scale. The aim of this paper is to synthesize the seismic evidences of the gas hydrates habitat, mainly using published data and a case study, in order to re-define the factors affecting the hydrate occurrence at the seismic scale. The seismic expression of several hydrate provinces often lacks a proper BSR. On the other hand, hydrate distribution appear to be connected with the underlying hydrocarbon system, able to concentrate fluid flow through different pathways, as well as strongly conditioned by the host lithology. In addition, the variation of P, T through time, due to e.g. erosion, uplift and climate changes imply that the BGHSZ is a dynamic boundary. These considerations have severe implication for the exploration of hydrate reservoirs, frequently characterized by patchy/discontinuous BSR and hydrocarbon leaking structures.

Methane Hydrate Field Program. Development of a Scientific Plan for a Methane Hydrate-Focused Marine Drilling, Logging and Coring Program

This topical report represents a pathway toward better understanding of the impact of marine methane hydrates on safety and seafloor stability and future collection of data that can be used by scientists, engineers, managers and planners to study climate change and to assess the feasibility of marine methane hydrate as a potential future energy resource. Our understanding of the occurrence, distribution and characteristics of marine methane hydrates is incomplete; therefore, research must continue to expand if methane hydrates are to be used as a future energy source. Exploring basins with methane hydrates has been occurring for over 30 years, but these efforts have been episodic in nature. To further our understanding, these efforts must be more regular and employ new techniques to capture more data. This plan identifies incomplete areas of methane hydrate research and offers solutions by systematically reviewing known methane hydrate “Science Challenges” and linking them with “Technical Challenges” and potential field program locations.