In the early 1990's the PI's developed an Ocean Bottom Absolute Gravity Meter (OBAGM) with funding from the Oceanographic Instrumentation Development program (proposal #89-20058). This system was then deployed on the Juan de Fuca ridge in 1994, 1995 and 1996. The PI's emplaced several seafloor benchmarks across the ridge and made gravity measurements on three of them (MG&G proposal #94-16939). This program was the initiation of a long-term monitoring program that will attempt to define cm-scale vertical deformation of the ridge.

During deployment of the sensors, and in subsequent land tests, the PI's have discovered a systematic error on the order of 1 mGal. If the instrument is operated outside of its pressure case, the measurements agree well with other land-based absolute gravity meters, indicating that the error source is vibrational coupling between the mechanical and optical components of the sensor. Although the PI's were able to correct for this systematic error, they propose here to redesign the system to eliminate the error, enabling the system to detect height changes of a few centimeters.

Agency
National Science Foundation (NSF)
Institute
Division of Ocean Sciences (OCE)
Application #
9820232
Program Officer
H. Lawrence Clark
Project Start
Project End
Budget Start
1999-03-01
Budget End
2003-02-28
Support Year
Fiscal Year
1998
Total Cost
$263,357
Indirect Cost
Name
University of California-San Diego Scripps Inst of Oceanography
Department
Type
DUNS #
City
La Jolla
State
CA
Country
United States
Zip Code
92093