Christchurch, the city that bore the brunt of the 2016 quake, wasn't even considered to be the place most at risk - the fault line that opened up there was a completely new one.

The risky place was supposed to be Wellington, which is right on the top of a known fault line.

Meanwhile Auckland, on the north island, which is not considered prone to big earthquakes, is built on the top of an active volcano, which will erupt at some stage in the future.

“It was very hard to breathe and without a gas mask we were gasping for air, but … adrenaline takes over. I’d rather break a few rules and save some lives than sit here wondering what we could have done.”
https://www.theguardian.com/world/2019/dec/10/new-zealand-volcano-helicopter-pilot-says...

Yeah I found that surprising as well. Imagine how the people felt who were waiting to get picked up, not knowing if or when a river of lava would be heading there way, or boulders falling out of the sky.

Some questions are being raised now as to why the island, which is privately owned, was allowed to operate as a tourist destination, given it was known to be highly active There had been a raised level of warning in November following increased earthquake activity, but seems like it was still not high alert. Apparently it is a 'steam' volcano, which is harder to predict than a normal one, but still...

Yes, it would have been terrifying on the island. Apart from the above, i understand it released a poisonous gas.

"50 people, in total, were on the island when it erupted. 23 have since been taken to shore. But it is currently too dangerous for police and rescue to visit the island, and up to 27 people remain."

It was an active volcano - last erupted in 2016 - but i guess no specific warning for this eruption. Some dramatic footage in the link.

https://youtu.be/bzTJAsvA1fE