Let’s talk about tsunamis.
Last Sunday night we had the Waihi Beach tsunami fiasco. Sirens went off and people panicked and headed for the hills only to find out it was a false alarm, there was no national emergency alert, it was a malfunction. A malfunction that made alarms go off in Waihi, Te Puke, the Mount and Omokoroa.
So people were a bit sniffy about their sleep being disturbed for no good reason, so we covered it on the radio on Monday.
In my afternoon show, I asked if you know what a tsunami warning sounds like versus a fire alarm for Voluntary Fire Services and this threw up something remarkable. We’re all over the shop. In some towns, the tsunami alarm is a long continuous wail from an air siren. In others, it’s a pulsating alarm.
We found out that in the Coromandel two towns 25 kilometres apart actually have the complete opposite alarms for fire and tsunami.
So I went wandering around the civil defence website and found that there is a standard alarm. It is a multiple tone signal that rises repeatedly with time. This signal can only be achieved with electronic sirens and it’s different to the signals used by emergency services. And they had a soundfile example. So we played it and it’s exactly the same as Newstalk ZB’s fire alarm.
So it’s a schemozzle. Someone picked a siren out of a catalogue. Local Civil Defence have their own rules and budget constraints so they’re not rushing out and getting it standardised. And the technical communication is bad which is why we had the false alarm malfunction. Needs work.
Now on the Mike Hosking Breakfast, I heard debate as to whether an expensive tsunami warning system is needed because, after all, who’s seen a tsunami in New Zealand lately.
It’s fair to say I didn’t understand tsunamis until the 2004 Boxing Day tsunami, which was an eye opener. I used to think it was a giant wave but in fact it’s an unstoppable surge. We saw that again at Fukushima and Samoa.
So I looked it up. New Zealand has experienced about 10 tsunamis higher than 5m since 1840. Some were caused by distant earthquakes, but most by seafloor quakes not far off the coast. A nearby coastal seafloor earthquake is the only warning people may get before a tsunami arrives.
The last significant tsunami to hit New Zealand was in 1960, caused by a magnitude 9.5 quake off the coast of Chile. It caused severe fluctuations in water levels along much of the country's east coast for several days, and damaged harbours, bridges, and coastal buildings.
There’s been some whoppers. Another Chile quake wiped out a Maori village on the Chathams leaving behind only sand and seaweed. One hit banks Peninsula and the surged right up the Canterbury Plains until it hit the foothills. A Wairarapa quake caused an 8 metre tsunami in Cook Strait and a 4 meter surge inside Wellington Harbour.
Our East Coast is most at risk because the big fault lies off shore. There’s also concerns that massive underwater landslides can spark them off. So tsunamis are very much a thing and we very much have to cope with them.
What interested me about this was the old, “I’ve never seen a tsunami so why should we bother” side to the debate. It’s a bit like the, “I’ve never felt an earthquake in Christchurch” stance that was around before there was an earthquake.
There’s a whole lot of others. “I’ve never seen a volcano erupt in Auckland”. “I’ve never seen Mount Taranaki erupt”. “I’ve lived beside this harbour for 40 years and the high tide mark hasn’t moved so tell me there’s global warming and the seas are rising.”
As science rules our lives more and more there are more and more people doubting science because they haven’t seen it with their own eyes. That’s not a good attitude.
It’s a post truth world where the term “expert” is often sneered at or used not as a compliment but an insult.
How did we get here?
I don’t know. But it's almost as if we're more afraid of experts than we are of tsunamis. And maybe that's because we're afraid that the experts will be proved right after all.