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Comment by jjcm | Hacker News Reader

> > So, the emergency sirens weren't used

> They weren't used because the website [1] specifically says that in the event of a siren you should "if you in a low laying area near the coastline; evacuate to high grounds, inland".

+1 to this. Everyone on the island knows those sirens. I was there in 2011 when the sirens went off to warn about the incoming tsunami from the Tohoku earthquake[0]. We packed sandwiches and water, and headed for high ground along with everyone else.

[0] https://en.wikipedia.org/wiki/2011_T%C5%8Dhoku_earthquake_an...

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Misuse of the sirens on one occasion might also cause people to hesitate in the future if there were to be a tsunami. And you really don’t have time to hesitate in that situation.

it's too bad when they were going to the trouble to install sirens all over "the last mile", they didn't think to have more than one alarm meaning.

The sirens are only along the coast. Not mountain side.

> The sirens are only along the coast. Not mountain side.

the better to lure sailors onto the rocks!

(the word Siren comes from Greek mythology, Siren's were "humanlike beings with very alluring voices, they appear in a scene in the Odyssey in which Odysseus" stops "the ears of his crew with wax so that they were deaf to the Sirens. Odysseus himself wanted to hear their song but had himself tied to the mast so that he would not be able to steer the ship off its course."

in latin languages such as Italian, "mermaid" is "la sirena")

Unless the sirens can produce different sounds that are easily distinguishable, then you can't have one alarm with two meanings when the meanings are absolutely not the same. If you hear the siren, how do you know if you need to pack your things to get out of the way of a fire or to seek higher ground from a tsunami where both of them might not be visible to you at the time of the siren?

Unless the response to the siren is the exact same thing, you can't use the siren for more than one thing.

> Unless the sirens can produce different sounds that are easily distinguishable

Sounds like something that would have to be done when installing (well, really speccing and buying) them.

It's too bad the sirens don't allow an ascending of frequency to mean "go to higher ground" and descending to mean "go to lower ground"

The Tsunami sirens in New Brighton (Christchurch, NZ) also have verbal output.

Does result in a strange "echo" because you hear other sirens talking delayed by the distance they are placed. But it does mean they can give extra info (e.g. during tests).

Here’s a crazy idea. You use one tone but you break it up.

One long for high ground three short for… huh, that’s new. What do? Oh it says here, fire get out now.

> One long for high ground three short for… huh, that’s new. What do? Oh it says here,

you just added a dependency for something that only had one meaning.

It's quite possible you are not familiar with how sirens work. The need constant air movement and make a continuous sound as the air is moving. These are the types of sirens that make the wind up sound before it gets to full speed, and then makes the wind down sound as they slow down. Think of air raid sirens from a WWII movie you might have seen. These are not the types of alarms you might be thinking of from your days in primary school

AFAIK, there were multiple patterns of sound that the sirens can generate, but it became confusing to keep them straight.

The patterns were published in the phone books, so the phone book's deprecation didn't help keep things going.

And so, the sirens' use got simplified, with the side effect of "oh crap, we no longer have a way to tell people about different emergencies".

I hope the use of the sirens to indicate more than one thing is brought back.

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