Study aims to detect collapsing volcanoes
When Mt St Helens erupted in 1980, it wasn’t a sudden blow that caused the deadliest and most destructive volcanic disaster in US history, but a sequence triggered by a much smaller event.
That happened to be a magnitude 5.1 earthquake which caused the volcano’s weakened north face to give way — and the resulting avalanche of debris kick-started the catastrophic eruption that killed 57 people and destroyed 250 homes.
It’s this kind of risk of collapse that scientists are now investigating in New Zealand, with a hope their research will save lives and infrastructure here.
The project’s leader, Dr Gabor Kereszturi of Massey University, said the country currently didn’t have any model to forecast these events.
“Volcanoes progressively weaken and may collapse without warning through hydrothermal alteration,” he explained.
“These dangerous mass-wasting processes occur less-frequently than eruptions or lahars but the resultant mass flows can be large, posing risk to local residents and businesses.”
Collapses were often multi-hazard events, with even small-scale landslides capable of triggering eruptions or creating break-out lahars.
Kereszturi singled out the Mt St Helens eruption as a particularly devastating example.
“Or the eruptions on the Upper Te Maari Craters on the northern side of Mt Tongariro in 2012, which caused small lahar or debris flow from near the eruption site down to State Highway 46.
“These kind of events demonstrated the greater need to understand and assess this process and its role in the volcanic hazard scape.”
The collaborative project, pulling together scientists from Massey University, the University of Canterbury and GNS Science, aims to create a new critical remote sensing technology capable of modelling how areas surrounding volcanoes may be affected.
The first-of-its-kind study would involve airborne surveys using aircraft mounted with a state-of-the-art hyperspectral imaging system, along with a digital camera.
Kereszturi expected this would vastly improve our understanding of volcanic risk — and how to make preparations ahead of an eruption.
While Mt Ruapehu had been chosen as the case study site, the team ultimately planned to apply the same model to Mt Taranaki, Mt Tongariro, Mt Tarawera, White Island and geothermal areas.