Publication Date:
2021-12-06
Description:
Super-eruptions, orders of magnitude larger than biggest eruptions experienced in historic
times, have devastated wide areas by pyroclastic flows, covered continent-size areas
by ash fallout, and injected large quantities of aerosols into the stratosphere affecting
global climate. The Youngest Toba Tuff (YTT) is the largest known super-eruption in
the Quaternary. Here we reconstructed the ultra-distal volcanic ash dispersal during
this super-eruption using a computational ash dispersal model, which provides insights into
the eruption dynamics and the impact of the event. The method uses a 3D time-dependent
tephra dispersion model, a set of wind fields, and several tens of thickness measurements
of the YTT tephra deposit. Results reveal that the YTT eruption dispersed ∼8600km3
(∼3800km3 dense rock equivalent, DRE) of ash, covering ∼40 million km2 with more than
5mm of ash. These new fallout volume estimations indicate that the total volume of the
material erupted (including the massive pyroclastic density current (PDC), 1500km3 DRE,
deposits on Sumatra) was ∼5300km3 DRE. Simulation results indicate that the eruption
had a very large mass flow rate and that the umbrella cloud, associated with the eruption
plume, spread as an enormous gravity current around the neutral buoyancy level. The
YTT tephra forms a key chronostratigraphic marker in the sedimentary sequences, and is
particularly useful for constraining the age of the palaeoenvironmental and archeological
records, and synchronizing these archives to investigate temporal relationships. These
new constraints on the extent of the YTT deposit are therefore particularly useful for
cryptotephra studies that aim to find nonvisible tephra layers for these chronological
purposes. This method used to constrain volcanological parameters of eruptions in the
past provides insights into the dispersal processes, and allows the amount of volatiles
released to be estimated which is crucial to assessing the impact of such events.
Description:
Published
Description:
ARTICLE 16
Description:
3V. Dinamiche e scenari eruttivi
Description:
N/A or not JCR
Description:
open
Keywords:
tephra dispersal
;
super-eruption
;
Toba
;
Youngest Toba Tuff
;
volcanic impact
;
04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
article
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