Subduction in Central and Southern Mexico (Invited)

Subduction in Mexico exhibits a wide range of along strike behaviors that are not easily explained by known variations in the Cocos Plate or the overriding continent. The central part of the region is characterized by flat subduction with a very weak and thin decoupling zone between the continent and slab. There is a large portion of the forearc that is missing and the (very) active arc itself is some 300 km from the trench. This contrasts with southern Mexico where the slab dips at 30-degrees dip and the arc is absent. There is also tomographic and converted-phase evidence of an opposing-dip slab that may have recently truncated the Cocos slab. Hydration levels estimated from Vs/Vp and Vs measurements indicate an increase in hydration towards the central (flat slab) portion of the subduction zone.