The objective was to analyze seafloor earthquake motion data for seismic active areas of southern California and the Arctic. The program focused on the use of the seafloor Earthquake Measurement System (SEMS) to collect and store seafloor seismic events. Offshore ground motions may differ from onshore motion in several aspects:
(1) Attenuation factors may be different in saturated soft and/or gassy seafloor soils;
(2) wave reflection within the water column may alter site-specific wave column;
(3) the wave reflection pattern may differ due to soil profiles; and
(4) the sediment profile may cause a focusing or defocusing of the seismic waves.
The results of this project will be used to evaluate the earthquake hazards of energy development and to provide data on design parameters.
Complete. The instruments were turned over to the State of California to continue gathering data. This data will be made available to the MMS.