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Deployment of a High-Sample-Rate Seafloor Geodetic System Across the Discovery Transform Fault

DOEI Project Funded: 2003

Proposed Research

In continental regions, deformation of the earth is routinely studied using geodetic techniques, such as Global Positioning Satellites, which detect motion of benchmarks installed in the earth's crust. Unlike seismometers, such systems do not require earthquakes to detect fault motion but can measure displacements that occur smoothly over long periods of time. However, this technology has not been easily exported to study crustal movements in the deep ocean environment. Developing high-precision geodetic measurement techniques for the seafloor is extremely important because more than half of the motion across oceanic plate boundaries occurs as smooth aseismic slip.

We are completing the development of an acoustic extensometer system that is capable of measuring displacements as small as 3 mm on the ocean floor. We will take advantage of two funded cruises to deploy it across the Discovery Transform Fault in the equatorial Pacific to investigate how slip occurs along this fault. If successful, this deployment will hopefully nucleate a significant new research program at WHOI that will address scientific questions in a variety of plate boundary environments.

Originally published: January 1, 2003