In January 1988 a seismic tomography experiment was carried out on the East Pacific Rise at 9 degrees 30'N to image in three- dimensions the seismic velocity structure of the rise axis. This experiment yielded a seismic data set consisting of more that 8000 records from approximately 500 shots and 15 ocean bottom seismometers. Initial results from the tomographic inversion of P wave delay times indicate substantial heterogeneity in structure both across and along the rise axis; for instance, the axial low velocity anomaly at 2 km depth is 1.5km/s slower than off axis; the along-axis variations in this velocity anomaly exceed 20%. This renewal will continue the investigation of seismic velocity models using improved inversion techniques, will explore methods of utilizing waveform amplitude information to constrain further the 3-D seismic structure, and will analyze and interpret the gravity, magnetic, and microearthquake data obtained during the course of the tomography experiment.

Agency
National Science Foundation (NSF)
Institute
Division of Ocean Sciences (OCE)
Application #
9000177
Program Officer
Bilal U. Haq
Project Start
Project End
Budget Start
1990-03-15
Budget End
1993-02-28
Support Year
Fiscal Year
1990
Total Cost
$176,836
Indirect Cost
Name
Massachusetts Institute of Technology
Department
Type
DUNS #
City
Cambridge
State
MA
Country
United States
Zip Code
02139