Western Mediterranean Ridge mud belt correlates with active shear strain at the prism-backstop geological contact

Abstract

A high-resolution swath-mapping survey conducted in the deep waters of the eastern Mediterranean Sea allowed mapping of active faults and mud volcanism along a sizable portion of the Mediterranean Ridge. Active shear is localized at the prism-backstop contact, a major dextral flower structure and a site of massive mud expulsion. We investigate the relationship between the mud output rate and horizontal strain rate by combining the mud volume estimate from sea-bottom reflectivity with kinematic modeling based on far-field global positioning system data and local fault and strain patterns. We find a direct correlation between maxima of mud output and maxima of the shear component of strain at the backstop contact. Mud volcanism may reflect the abundance of solid (mud) and fluid (methane) sources combined with a favorable tectonic regime established at the prism-backstop contact in post-Pliocene time, in relation to plate tectonic changes.