Pink pumice and deep sea volcanic eruptions

On January 14, 2022, a mega volcanic eruption in Tonga (southern Pacific Ocean) sent a powerful shock wave across the globe. With tsunami waves up to 15 m and an energy estimated equivalent to 4 to 18 megatons of TNT, this catastrophic explosion reminds us that our planet is very much alive.

Members of the Tonga Geological Survey observe the Hunga Tonga-Hunga Ha'apai volcano eruption in Tonga. (Photo Tonga Geological Services of the Government of Tonga/Xinhua)

Dr. Eric Ferré of our school of geosciences is involved in a study of a similarly violent, albeit smaller, submarine explosion in the same region. The Havre submarine volcano, located in the Kermadec Islands, lies between ~1500 and 600 m below the sea surface. The 2012 Havre eruption of this volcano is the largest recorded silicic submarine eruption in history (~1.5 km3) and was unobserved until a very large field of floating volcanic rock (pumice) was found by boats sailing in the area.
A more recent (2019) example of a gigantic floating field of pumice is shown in the video below.

Dr. Ferré's research on the magnetic properties of the pumice, in collaboration with one of his former students, Joe Knafelc, now at Queensland University of Technology (QUT), in Brisbane Australia and Dr. Scott Bryan and Dr. Michael Jones, also at QUT, is summarized in their article Havre 2012 pink pumice is evidence of a short-lived, deep-sea, magnetite nanolite-driven explosive eruption in Communications in Earth and Environment. The magnetic measurements in this study, performed at the University of Louisiana at Lafayette, helped constrain the duration of the 2012 Havre eruption through the identification of magnetite nanolites, which are thought to have triggered the eruption.

Residents of Louisiana can relax ... there are no known seamounts or submarine volcanoes in the Gulf of Mexico!