Volcano cannon test for Kiwi houses
Engineering scientists have been firing rocks at a typical New Zealand roof to see the effect when a volcano erupts nearby.
‘‘If there is a volcanic eruption in Auckland and people need to shelter in place, these types of tests give us some insight as to what level of protection New Zealand buildings may give us,’’ said Thomas Wilson, a professor of disaster risk and resilience at the University of Canterbury.
‘‘If we are able to understand what the impacts of these volcanic hazards are on specific New Zealand-designed buildings and built to New Zealand building codes, that provides us much more understanding of what the potential rebuild or repair costs may be,’’ Wilson said. The research is part funded by the Earthquake Commission (EQC).
The researchers built a typical roof complete with rain gutters and loaded it with ‘‘tephra’’, which is the solid stuff that comes out of erupting volcanoes such as ash, pebbles and small rocks.
Then the scientists loaded a ‘‘volcano cannon’’ – really a compressed air device – and fired larger rocks at the roof.
They were interested in ‘‘what kind of impacts we get from volcanic ballistic projectiles’’, said Nicole Allen, a PhD candidate in the school of earth and environment.
The research is still under way and results are not yet available but the scenario studied in a video released by the EQC supposes that a roof has been loaded with tephra from an earlier eruption phase, followed by a projectile phase.
There are many scenarios for an Auckland eruption and scientists are working through them. While some warning might be hoped for, evacuating 1.6 million people would take time and people might have to shelter in place. ‘‘Auckland sits on an active volcanic field with 53 known volcanic centres and it is likely there will be an eruption in the future, we just aren’t sure when or where,’’ Wilson said.
The last eruption was Rangitoto about 600 years ago. The Auckland volcanic field triggers small eruptions in new locations, rather than the massive eruptions of the central North Island.