PT  - JOURNAL ARTICLE
AU  - Jaxybulatov, K.
AU  - Shapiro, N. M.
AU  - Koulakov, I.
AU  - Mordret, A.
AU  - Landès, M.
AU  - Sens-Schönfelder, C.
TI  - A large magmatic sill complex beneath the Toba caldera
AID  - 10.1126/science.1258582
DP  - 2014 Oct 31
TA  - Science
PG  - 617--619
VI  - 346
IP  - 6209
4099  - http://science.sciencemag.org/content/346/6209/617.short
4100  - http://science.sciencemag.org/content/346/6209/617.full
SO  - Science2014 Oct 31; 346
AB  - Volcanic super-eruptions eject thousands of times the volume of the largest documented eruptions over human history. Several “supervolcanoes” capable of this type of unimaginable devastation dot the surface of Earth today. Jaxybulatov et al. use seismic background noise to estimate the size and maturity of one of the world's largest volcanic reservoirs, the Toba caldera in northern Sumatra. Magma storage under the caldera occurs slowly over time, in the form of horizontal layers of magma injected into the crust. These magmatic sills are documented to 20 kilometers below the surface, but more sills could exist even deeper. The characterization of magma storage in large volcanic systems may help us to prepare for future volcanic super-eruptions.Science, this issue p. 617An understanding of the formation of large magmatic reservoirs is a key issue for the evaluation of possible strong volcanic eruptions in the future. We estimated the size and level of maturity of one of the largest volcanic reservoirs, based on radial seismic anisotropy. We used ambient-noise seismic tomography below the Toba caldera (in northern Sumatra) to observe the anisotropy that we interpret as the expression of a fine-scale layering caused by the presence of many partially molten sills in the crust below 7 kilometers. This result demonstrates that the magmatic reservoirs of present (non-eroded) supervolcanoes can be formed as large sill complexes and supports the concept of the long-term incremental evolution of magma bodies that lead to the largest volcanic eruptions.