Work

Plate Interactions and Mantle Flows Beneath the Caribbean and Adjacent Regions Revealed by P‐Wave Anisotropic Tomography

Year: 2026

Type: article

Abstract: We determine the first P‐wave azimuthal and radial anisotropy tomography beneath the Caribbean and its adjacent regions. The Cocos and Atlantic Plates are imaged as high‐velocity (high‐V) zones down to ∼1,600 km depth and they have subducted independently beneath the Caribbean Plate. A high‐V zone adjacent to the Nazca slab, characterized by continuous seismicity and downward extension to 200 km depth, is considered to be the subducted Caribbean slab. The Cocos plate is imaged as a high‐V zone that is torn into two parts below 300 km depth along the Motagua Polochic fault zone. Trench‐parallel and toroidal FVDs (fast velocity directions) exist in low‐velocity (low‐V) anomalies above and below the southern Cocos slab and around the Panama, respectively, which may reflect large‐scale toroidal mantle flow around the southern Cocos slab, bypassing the Panama, from the asthenosphere to the mantle wedge. Azimuthal anisotropy in the Lesser Antilles shows a trench‐normal FVDs in the subducted Atlantic slab, perpendicular to seafloor isochrons of plate reconstruction. Above the Atlantic slab, a low‐V zone with negative radial anisotropy reflects widespread vertical mantle flow, which appears not only in the upper mantle but also in the mantle transition zone and lower mantle. Beneath the Colombia‐Ecuador volcanic arc, low‐V anomalies passing through and surrounding a slab gap exhibit positive radial anisotropy. This feature indicates that horizontal mantle flow occurs in the mantle wedge and also originates from asthenosphere entering into the mantle wedge through a slab tear.

Source: Tectonics

Authors: Qingyu Qiao, You Tian, Dapeng Zhao, Xin Liu

Institutions: Jilin University, Tohoku University, Ocean University of China

Language: English

Topic: Geological and Tectonic Studies in Latin America

Subfield: Geophysics

Field: Earth and Planetary Sciences

Domain: Physical Sciences

Open Access status: hybrid

Estimated APC paid: $4,070

Funders: Japan Society for the Promotion of Science, National Key Research and Development Program of China

Awards: Tomographic imaging of large earthquake source zones, G5727026088, G5976533801