Finite-Frequency Tomography Reveals a Variety of Plumes in the Mantle

TLDR

We present tomographic evidence for the existence of deep‑mantle thermal convection plumes. P‑wave velocity images reveal at least six well‑resolved plumes—Ascension, Azores, Canary, Easter, Samoa, and Tahiti—extending into the lowermost mantle, with additional less‑resolved plumes such as Hawaii potentially reaching that depth, several plumes confined to the upper mantle implying a two‑regime convection, and all plumes spanning several hundred kilometres, indicating they carry a substantial fraction of Earth’s internal heat.

Abstract

We present tomographic evidence for the existence of deep-mantle thermal convection plumes. P-wave velocity images show at least six well-resolved plumes that extend into the lowermost mantle: Ascension, Azores, Canary, Easter, Samoa, and Tahiti. Other less well-resolved plumes, including Hawaii, may also reach the lowermost mantle. We also see several plumes that are mostly confined to the upper mantle, suggesting that convection may be partially separated into two depth regimes. All of the observed plumes have diameters of several hundred kilometers, indicating that plumes convey a substantial fraction of the internal heat escaping from Earth.