Intellectual Merit: The project entails a re-analysis of a 3-d multichannel seismic data set obtained from the Lucky Strike volcano, Mid-Atlantic Ridge during the French-sponsored SISMOMAR cruise in 2005, and data from a larger-scale ocean bottom seismic tomographic experiment in the same region. The original analysis of these data by a French-led group shows clear evidence for an extensive magma lens beneath the Mid-Atlantic Ridge. In order to look at finer-scale structure, and particularly to distinguish between melt-rich vs crystal-laden sections of the magma body (a question of great importance to the marine geoscience community), the PIs intend to employ a prestack imaging approach which requires detailed knowledge of shallow crustal structure. The method proposed to achieve this, SOBE (synthetic ocean bottom experiment) should enable high resolution tomography of multichannel seismic data. This is a wave equation solution that extrapolates sources and receivers to the seafloor and enables detection of the shallowest refracted arrivals recorded on the MCS streamer that otherwise are hidden in the water waves. SOBE should provide vertical resolution on the order of 10s of meters to provide the structural controls required for prestack imaging, and should also make it possible to highlight the upper crustal fluid pathways and fractures that may be linking melt-rich zones to the hydrothermal vent fields. If the SOBE method can be proven through the analysis of this existing data set, it has the potential to transform marine multichannel seismic investigations.
Broader Impacts: Broader impacts include capacity building for MCS data analysis and interpretation, and distribution of visualization products for public viewing through the RidgeView website, and at an HD stereo projection theatre at the Paine Forum. The project includes research and training experiences for a graduate student to be split funded between US and French institutions.
