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Volcanoes and Their Products
Published in Dexter Perkins, Kevin R. Henke, Adam C. Simon, Lance D. Yarbrough, Earth Materials, 2019
Dexter Perkins, Kevin R. Henke, Adam C. Simon, Lance D. Yarbrough
In 1982, Chris Newhall of the United States Geological Survey and Stephen Self at the University of Hawaii developed a quantitative measure to compare volcano explosiveness: the volcanic explosivity index (VEI). This index is based primarily on the volume of pyroclastic material ejected by the volcano, with some consideration of eruption column height and duration of eruption. The VEI scale is a logarithmic scale. A volcano with a VEI of 6, then, is 10 times more powerful than one with a VEI of 5, and 100 times more powerful than a volcano with a VEI of 4. As shown in Figure 7.33, the VEI scale correlates well with eruption types. Volcanoes with low VEI (Hawaiian or Strombolian type) are commonplace today, but those with high index (ultra-Plinian) occur rarely. Only four eruptions with VEI of 7, and none with VEI of 8, have occurred during the past 10,000 years. Supervolcanoes are exceptionally rare. Toba, 74,000 years ago, was the last one.
Taupō: an overview of New Zealand's youngest supervolcano
Published in New Zealand Journal of Geology and Geophysics, 2021
Simon J. Barker, Colin J.N. Wilson, Finnigan Illsley-Kemp, Graham S. Leonard, Eleanor R.H. Mestel, Kate Mauriohooho, Bruce L.A. Charlier
For the future, the installation of 13 broadband seismometers around Lake Taupō as part of the ECLIPSE (Eruption or Catastrophe: Learning to Implement Preparedness for future Supervolcano Eruptions) research programme (Illsley-Kemp et al. 2020) is aimed at an improved detection and location of earthquakes, and direct seismic-imaging of the magma system beneath Taupō (Figure 10). This information will be vital for interpreting future unrest episodes and will improve our understanding of the processes that operate under New Zealand's hyperactive supervolcano.