@Smokin Joe @TomSea
It smoked, steamed and roared - then blew up: Terrifying warning signs New Zealand's White Island volcano was about to erupt - as it's revealed 24 Australians are caught in the carnage
https://www.dailymail.co.uk/news/article-7771185/The-terrifying-warning-signs-New-Zealands-White-Island-volcano-erupt.html
...'It showed increased activity for the last few weeks and so we raised the alert level,' GeoNet Project Director Dr Ken Gledhill told a press conference on Monday afternoon.
'It has quietened down, but we can't be certain there won't be another eruption in the next 24 hours.'...
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What scientists say about the volcano
https://www.newsroom.co.nz/2019/12/10/942023/whaakari-white-island-what-scientists-say#
...Increased alert level before the eruption
In mid-November, the alert level lifted to 2.
At the time, GNS volcanologist Michael Rosenburg said there had been an increase of sulphur gas from deep inside the volcano and an increase in tremors.
He said the changes may or may not be a signal that something is happening.
"White Island volcano is really complicated and just because one thing changes, it doesn't necessarily mean that everything else will change and it doesn't necessarily mean that this is going to lead to an eruption."
Dr Sherburn said GNS had seen increased seismic activity - specifically volcanic tremor - over the past month or so....
[/quote]Such data are almost always examined in retrospect, saying it was clear...
It's never clear that an eruption will happen at any given time or date until it is happening.
Otherwise, even though risk classifications may be elevated (part science, and part CYA):
He said the changes may or may not be a signal that something is happening.
That's done for a reason, of course, just the same as with earthquakes.
For one thing, it's honest. (You really can't
know when, just that it looks like it
could, unless, of course, it is erupting.)
If it fails to happen, you're the boy who cried "Wolf!", who, if you will recall, ended up getting eaten by the very thing he warned about, albeit with a long history of false alarms.
In addition, there might be a host of nasty things from such a false alarm, when the comfort of an attempt to keep people safe is overwhelmed by the notion that a lot of money didn't change hands. After all, the threat of apocalyptic destruction, even on a small scale, is bad for business.
It is a quandry that has plagued seismologists and volcanologists for some time, now. You even see the conflict between people's safety and economic concerns played out in the movies.
