Effects of Seafloor Bathymetry on the Imaging of Magma Chamber Reflectors

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Mid-ocean ridges are the site of volcanic activity as the new ocean crust is generated. An important question about this activity is whether as it ascends the magma collects in a chamber below the axis of the ridge, and if so, what is the size and extent of the chamber. Recent seismic data collected on the East Pacific Rise show a reflector that has been interpreted as the top of a magma chamber. This reflector is present on along-axis and cross-axis profiles. At locations where the ridge axis is relatively broad and flat the reflector is 3-4 km wide while in locations where the ridge axis is narrow and rough the reflector is less than 1 km wide. The objective of this project is to determine if the observed difference in the width of the reflector is due indeed to a difference in the width of the magma chamber or might instead be due to refraction and diffraction of the seismic energy by the seafloor. The principal investigator will reanalyze the seismic data using a technique that can account for energy refractiona and diffraction at the seafloor.