Broadband Tomography Under Costa Rica and Nicaragua

This broadband array provides imaging of the subducting plate, mantle wedge and overlying lithosphere beneath the Central American arc in Nicaragua and Costa Rica. It forms a key element of the MARGINS Subduction Factory focus site efforts in Central America, with a goal of understanding magma formation beneath arcs in a place that exhibits large along-strike gradients in arc geochemistry. The array features two dense lines, 10 km spacing, one through central Nicaragua where flux of slab-derived fluids reaches a global maximum, and a second through northern Costa Rica where magmas show little geochemical signature of subducting sediments. Sparser cross lines provide sampling of along-strike variations in the arc, and control in the backarc. Primary studies include imaging with scattered teleseismic coda, P,S, and attenuation tomography, shear wave splitting, surface wave imaging, and studies of earthquake sources.