The feeder system of the Toba supervolcano from the slab to the shallow reservoir

Ivan Koulakov (1, 2) , Ekaterina Kasatkina (1) , Nikolai M Shapiro (3, 4) , Claude Jaupart (3) , Alexander Vasilevsky (1, 2) , Sami El Khrepy (5, 6) , Nassir Al-Arifi (5) , Sergey Smirnov (7, 8)

1 NSU - Novosibirsk State University
2 IPGG SB RAS - ​Trofimuk Institute of Petroleum Geology and Geophysics of the Siberian Branch of the RAS
3 IPGP - Institut de Physique du Globe de Paris
4 Institute of Volcanology and Seismology of the RAS
5 KSU - King Saud University [Riyadh]
6 NRIAG - National Research Institute of Astronomy and Geophysics [Helwan]
7 Sobolev Institute of Geology and Mineralogy [Novosibirsk]
8 TSU - Tomsk State University

The Toba Caldera has been the site of several large explosive eruptions in the recent geological past, including the world's largest Pleistocene eruption 74,000 years ago. The major cause of this particular behaviour may be the subduction of the fluid-rich Investigator Fracture Zone directly beneath the continental crust of Sumatra and possible tear of the slab. Here we show a new seismic tomography model, which clearly reveals a complex multilevel plumbing system beneath Toba. Large amounts of volatiles originate in the subducting slab at a depth of B150 km, migrate upward and cause active melting in the mantle wedge. The volatile-rich basic magmas accumulate at the base of the crust in a B50,000 km 3 reservoir. The overheated volatiles continue ascending through the crust and cause melting of the upper crust rocks. This leads to the formation of a shallow crustal reservoir that is directly responsible for the supereruptions.

Domains: Volcanology; Tectonics

Ivan Koulakov, Ekaterina Kasatkina, Nikolai M Shapiro, Claude Jaupart, Alexander Vasilevsky, et al.. The feeder system of the Toba supervolcano from the slab to the shallow reservoir. Nature Communications, 2016, 7, pp.12228. ⟨10.1038/ncomms12228⟩. ⟨insu-02274849⟩