Havre Ash - A Deep-Sea Mystery
The sea floor at Havre volcano at ~1000 m depth is littered with volcanic ash. (Photo courstesy of J.D.L. White)
In July 2012, Havre seamount, a rhyolitic volcano situated at ~1,000 m depth below sea level, erupted. Since this volcano is located quite remotely in the Kermadec arc, North-West of New Zealand (~ 1,000 km North of Auckland), this event would probably not have been discovered if the eruption wouldn't have produced an large pumice raft, which covered~400 km2 of sea surface [1].
Three years later, a maritime expedition was sent out to map the eruption site with high resolution, and to apply an RUV (remote underwater vehicle) to investigate the scene and to retriev geological samples [2].
Besides lava flows and giant pieces of drowned pumice, it was the presence of an abundance of fine ash, which was most surprising. Alone in the mapped area the total volume of erupted ash must substantially exceed 0.1 km3 in the mapped area. But although an area of over 35 km2 was probed, no thinning trend could be established, which means that to this date no maximum estimate can be made [3].
Our research focussed on the Havre ash particles and the fingerprints they carry. Our main goal was to unravel the "Havre mystery" and find out what has happened in July 2012 on the bottom of the deep-sea.
The following pages will describe our considerations and approaches leading us to establish a new ash generation mechanism, which bears the potential to change our current view on the existence of explosive deep-sea volcanism. We baptized this mechanism "Induced Fuel Coolant Interaction" (IFCI) [4].
-> Explosive fuel-coolant interaction
-> Why fine volcanic ash particles are good eye witnesses
Annotations:
The Havre ash project was funded by a Marsden grant, New Zealand.
The lines of thought above are based on considerations detailed in Dürig et al. (2020) [4], if not cited otherwise. Please let me know if you have any comment or suggestions for changes. My email address is: tobi[at]hi.is
References and Annotations
[1]: M. Jutzeler, R. Marsh, R. J. Carey, J. D. L. White, P. J. Talling, L. Karlstrom, On the fate of pumice rafts formed during the 2012 Havre submarine eruption. Nature Communications 5 (2014).
[2]: R. J. Carey, S. Adam Soule, M. Manga, J. D. L. White, J. McPhie, R. Wysoczanski, M. Jutzeler, K. Tani, D. Yoerger, D. Fornari, F. Caratori-Tontini, B. Houghton, S. Mitchell, F. Ikegami, C. Conway, A. Murch, K. Fauria, M. Jones, R. Cahalan, W. McKenzie, The largest deep-ocean silicic volcanic eruption of the past century. Science Advances (2018).
[3]: A. P. Murch, J. D. L. White, R. J. Carey, Characteristics and Deposit Stratigraphy of Submarine-Erupted Silicic Ash, Havre Volcano, Kermadec Arc, New Zealand. Front. Earth Science 7, 1–21 (2019)