Slow-moving and far-travelled dense pyroclastic flows during the Peach Spring super-eruption

Nature Communications
By: , and 

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Abstract

Explosive volcanic super-eruptions of several hundred cubic kilometres or more generate long run-out pyroclastic density currents the dynamics of which are poorly understood and controversial. Deposits of one such event in the southwestern USA, the 18.8 Ma Peach Spring Tuff, were formed by pyroclastic flows that travelled >170km from the eruptive centre and entrained blocks up to ~70–90cm diameter from the substrates along the flow paths. Here we combine these data with new experimental results to show that the flow’s base had high-particle concentration and relatively modest speeds of ~5–20ms−1, fed by an eruption discharging magma at rates up to ~107–108m3s−1 for a minimum of 2.5–10h. We conclude that sustained high-eruption discharge and long-lived high-pore pressure in dense granular dispersion can be more important than large initial velocity and turbulent transport with dilute suspension in promoting long pyroclastic flow distance.

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Publication type Article
Publication Subtype Journal Article
Title Slow-moving and far-travelled dense pyroclastic flows during the Peach Spring super-eruption
Series title Nature Communications
DOI 10.1038/ncomms10890
Volume 7
Year Published 2016
Language English
Publisher Nature Publishing Group
Contributing office(s) Geology, Minerals, Energy, and Geophysics Science Center
Description Article 10890; 8 p.
First page 1
Last page 8
Country United States
State Arizona, California, Nevada
Online Only (Y/N) N
Additional Online Files (Y/N) N
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