Where does 80m of molten rock end up?
Wherever it wants.
Apparently, if the next Auckland volcano is in the worst possible location, 500000 people might need to be evacuated. Even in a better location it will be no fun at all, with the only redeeming feature being that even Peter Thompson will have to concede that it’s not the best time to buy a house. It’s good that research and planning is underway, so the mayor’s office will have a set of contingency plans filed under “V” for when the next eruption happens, but the need for public panic awareness is perhaps less than for the Alpine Fault.
From a statistical viewpoint, there are two factors that go into how much you should do to prepare for an emergency: how likely it is, and how much the preparation will help. The earthquake wins on both of these: it’s about ten times as likely in the next 50 years, and we can do a lot more to reduce the damage. With the Alpine Fault, we need to decide how much to spend on strengthening roads, bridges, and houses, and making water and sewer systems less likely to break. Public discussion and pressure on the government are important. On the other hand, if a river of molten rock heads south from One Tree Hill, or a chunk of tuff the size of a refrigerator lands on my roof, my house isn’t going to survive no matter how good the building standards are.
In terms of things we can actually influence, we might want to worry more about which bits of Auckland will be under water in 50-100 years, not which bits will be under lava.
Thomas Lumley (@tslumley) is Professor of Biostatistics at the University of Auckland. His research interests include semiparametric models, survey sampling, statistical computing, foundations of statistics, and whatever methodological problems his medical collaborators come up with. He also blogs at Biased and Inefficient See all posts by Thomas Lumley »
Seems to me that the Herald angle on the story is flawed because it assumes that the existing volcanoes will re-erupt. It mentions “lava streaming down Mt Eden” and all the circles are centered on existing volcanoes.
But all those volcanoes are extinct. Our volcanoes arise from bubbles in a magma field that rise like bubbles in champagne. So the next eruption could be anywhere – most likely between existing cones. So lave is more likely to be flowing UP Mt Eden than down.
The paper doesn’t have this angle and nor does the Stuff version at http://www.stuff.co.nz/auckland/local-news/7533001/No-warning-before-volcanic-eruption which actually starts off with “Lava vents are likely to appear in new places rather than existing volcanoes, the study says.”
The paper itself is available from the Herald web site. To find it use Google to search for “LiDAR-based quantification of lava flow susceptibility in the City of Auckland”
12 years ago