The Great Meteor seamount: seismic structure of a submerged intraplate volcano

Abstract

During R/V METEOR cruise No. 12/2 in summer 1990, an OBH airgun refraction line was shot across the Great Meteor seamount, Northeast Atlantic. Velocity structure was modeled using 1-dimensional velocity analysis and 2-dimensional ray tracing of P-wave travel times. The results represent a seismic image of a submerged intraplate volcano. Upper crustal and apron P-velocities of the seamount are significantly lower than those observed in the oceanic layer 2. We interpreted these low velocities in terms of extrusive lavas and of debris flows with high average porosities. At 3 km beneath the seamount summit, the core of the edifice appears to be dominantly intrusive, with P-velocities >6.0 km/s. A distinct high-velocity body (P-velocities >6.5 km/s) suggests a central conduit or a plutonic suite. Weak evidence was found for the existence of a subcrustal plutonic complex with P-velocities intermediate between those of layer 3 and the upper mantle as it is typical for many volcanic islands.