Volcanoes: Expedition sets sail to explore under-studied hazards of Bay of Plenty volcanoes

Tūhua/Mayor Island.

Researchers will study the multiple natural hazards posed by two Bay of Plenty volcanoes this month including their potential to generate tsunami, ashfall and pyroclastic flows of hot ash and gas.

Scientists from multiple agencies will set sail on RV Tangaroa tomorrow to build knowledge of the anatomy of the mostly submerged Tūhua/Mayor and Whakaari/White islands, GNS Science said.

GNS Science, Victoria University of Wellington and Scripps Institute of Oceanography (USA) will join the Beneath the Waves expedition to study the two offshore volcanoes’ geologic history, including previous eruptions and flank collapses, both of which can generate tsunamis.

“The team of researchers will deploy cutting-edge research instruments around the islands to collect new data on the islands’ magmatic and hydrothermal systems and search for evidence of past eruptions hidden in seabed sediment layers,” GNS Science said.

“Understanding the internal plumbing systems of these islands will improve how we interpret indicators from volcano monitoring data, advise emergency preparedness and response and importantly, inform the development of mitigation strategies to protect local Bay of Plenty communities against future volcanic events,” senior volcano geophysicist and programme leader, Craig Miller, said.

“Fully quantifying volcano-hazard potential requires complete understanding of a volcano’s anatomy, history, and dynamic hazard processes.”

The expedition from October 12 to 25 will undertake two deployments of 40 ocean-bottom electromagnetic receivers to image the locations of the magma systems that drive eruptions beneath the island volcanoes.

Ocean Bottom Electro Magnetic instrument by Whakaari/White Island.

Ash layers from previous eruptions buried in seabed sediment will be collected using piston cores.

Analysis of the sediment layers will help identify how often and how large ash-forming eruptions and pyroclastic density currents occurred in the past and improve long-term probability forecasts of future eruptions.

“The Beneath the Waves programme uses multiple innovative methods to image these volcanoes and build a comprehensive picture of a range of hazard scenarios,” Miller said.

“So, when future events occur, whether an eruption or a tsunami, or both, we know what to expect and are prepared for all possible hazard impacts.”

Beneath the Waves is a GNS-led MBIE Endeavour programme delivered with collaborators from University of Canterbury, Massey University, Victoria University of Wellington, East Coast Labs and Bay of Plenty Civil Defence and Emergency Management.