CD tsunami warning 30 July

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snj

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#3399022 1-Aug-2025 09:45

cddt:

So my iPhone once again received the alerts, but didn't play a sound. I have the alerts enabled, but it remained silent when the notification popped up. This happened last time we had an alert so I was fiddling with the settings trying to work out how to unsilence it, but no luck!

Were you actively using the iPhone at the time? I've noticed this before but I'm pretty sure it's coincided with me actively using the iPhone at the time (unlocked and in an app) I think, so it's just pushed the notification to front of screen while notifications on other devices have gone off.

The only other thing I can think of that might've changed in my use is that I did have the media volume up when the last two alerts went out, but that shouldn't affect the alert sounds (at least I hope not - I normally have the media/speaker volume down to 0 unless I actively want to hear something to avoid surprise bursts of sounds from ads/etc in quiet settings).

cddt

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#3399028 1-Aug-2025 10:30

snj:

Were you actively using the iPhone at the time? I've noticed this before but I'm pretty sure it's coincided with me actively using the iPhone at the time (unlocked and in an app) I think, so it's just pushed the notification to front of screen while notifications on other devices have gone off.

The only other thing I can think of that might've changed in my use is that I did have the media volume up when the last two alerts went out, but that shouldn't affect the alert sounds (at least I hope not - I normally have the media/speaker volume down to 0 unless I actively want to hear something to avoid surprise bursts of sounds from ads/etc in quiet settings).

Nope I wasn't using the phone at the time. I knew the alert had come out because it was nearby and the screen lit up.

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MadEngineer

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#3399062 1-Aug-2025 13:27

alisam:

I got the alert.

However, I couldn't bear the noise and so decided to confirm the prompt (I am now trying to remember) and assumed I could retrieve the message without the sound.

I made a mistake, and I cannot find it, to re-read it.

I'll be ready next time to lower the volume to zero.

On both my iPhone and Android phone, hitting volume down once muted the noise yet kept the message on the screen - the same action as used to ignore an incoming phone call.

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Wellingtondave

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#3399135 1-Aug-2025 20:57

Anyone modified their phones not to receive alerts? Curious as to how you do this whilst still accepting the security updates or do you have to change the setting after every update?

JimmyH

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#3405872 20-Aug-2025 16:47

Mrcutiepatootie:

I get that it’s an emergency and I’d appreciate if I lived in Japan or close to where it happened, but they’ve sent out these alerts as if the tsunami’s going across the pacific to get here. More of a nuisance than an emergency if anything.

Except it wasn't an emergency, not even remotely.

It was thousands of kilometres away and the Pacific Ocean is huge. Not only does the height of waves reduce as they get further away from the trigger point, they take time (many hours) to cross that much space. Along the way there's satellite surveillance (which can track tsunamis) and terrestrial monitoring stations. They would know hours in advance if there was a huge wave coming, and how big it was likely to be. But there wasn't. It was (depending on where you were) 20-30cm. Not exactly a huge risk to life and limb - a good Wellington southerly will kick up much more than that.

They jumped the gun, probably over-excited to be relevant to something at last. If they had waited for data there would still have been plenty of time to issue a warning. Except they didn't. What they did was irritate huge numbers of people with a totally unnecessary disruption "because they can". I know several people who have gone into their phones and disabled reception for these types of alerts. It's a bit complicated because they purposefully try and stop it from being able to be disabled. But it can be done, I have the instructions, and frankly I'm thinking of doing it too. Not, I venture to suggest, the effect they should be aiming for.

The phrase: "Wolf, wolf, wolf......." springs to mind.

RunningMan

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#3405879 20-Aug-2025 17:25

JimmyH:[snip] It was (depending on where you were) 20-30cm. Not exactly a huge risk to life and limb - a good Wellington southerly will kick up much more than that.

Suggest you learn a little about the energy in a 20-30cm tsunami vs a 20-30cm swell. A tsunami wave rather than being a couple of metres in length (i.e. peak-peak) may be multiple kilometres. That's several orders of magnitude more energy for the same wave height. Don't get fooled into thinking it's like a normal wind blown wave of the same height because it isn't.

Have a read of this for a start. https://www.noaa.gov/jetstream/tsunamis/tsunami-propagation/jetstream-max-tsunamis-vs-wind-waves

EDIT: here you go:

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quickymart

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#3405908 20-Aug-2025 18:40

Some issues identified: https://www.rnz.co.nz/news/national/570510/nema-identifies-mobile-phone-alert-problems-during-tsunami-warning

Oblivian

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#3405915 20-Aug-2025 19:00

Sure some stretches with the updating phones theory?. Reliant on manufacturers OTA release schedule. And for them to all be on that particular day?...

Quite the politician way to say 'its a you thing not an us issue'

Many here in chc we well Inland. But obviously there's no 'Iemi has been successfully altered' flag. Or a chunk of their theories would likely vanish.

RunningMan

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#3405921 20-Aug-2025 19:32

Oblivian:

Sure some stretches with the updating phones theory?.

Actually not on this occasion. By chance that day there was an iOS update released that by default iPhones will auto install overnight. The update triggers a reboot and the reboot triggers the warning to be re-notified. I remember manually forcing the update on several iOS devices that evening and as each rebooted the warning hit again (and again, and again!).

EDIT: It was iOS 18.6 released that day.

alasta

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#3405992 21-Aug-2025 10:50

Based on the RNZ article linked above, the two notifications on my phone appear to have correctly coincided with when they were sent out, and I have a pretty good theory as to why I received a repeat on my Apple Watch.

When I swim at my local pool my phone is in a locker at the poolside. Water attenuates cellular and bluetooth signals, so the watch probably connects intermittently to cellular depending on the availability of the patchy signals from the cellular network, and the bluetooth connection to my phone. At some point during the swim it's connected to the cellular network which has determined that the SIM in my watch has not yet received the alert, hence sending it through at that moment.

I think NEMA's response is similar what what you'd expect of a corporate IT department. They're shifting the blame to the inherent limitations of the technology, but ignoring the bigger question as to whether those limitations make the whole system impractical and unviable.

snj

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#3406123 21-Aug-2025 13:53

alasta:

I think NEMA's response is similar what what you'd expect of a corporate IT department. They're shifting the blame to the inherent limitations of the technology, but ignoring the bigger question as to whether those limitations make the whole system impractical and unviable.

I think this is the key question, what are other countries doing in this regard, for instance is NZ leaving alert broadcasts active for too long?

Alternatively, should NEMA actually be taking advantage of the limitations more than they are? Map towers that are serving coastal communities send the same message to both areas but expire the more inland areas within the hour or whatever, and then only risk duplicate notifications for people that might be arriving into those coastal communities that might not have already seen the broadcast? (Or alternatively slightly different wording "Coastal Risk Area", "Coastal Proximity Risk Area" sort of thing.

They've certainly got the ability to target small clusters of towers, for instance during the Muriwai slips, I believe they sent out a bunch of alerts just to the Muriwai community with the essential information, seems with the planning they could split the current Tsunami alert zone into Set A and Set B and do something like that.

I do have a question for anyone currently working in the telco sector and might have knowledge, but does the Cell Broadcast system actually have a "Alert/Notification ID" field? I can see that https://en.wikipedia.org/wiki/Cell_Broadcast shows there is the 3GPP Hex for what type of alert is broadcast (NZ/NEMA/FENZ uses 1112 I guess since we can't opt out), but I can't find anything about an alert ID/similar. Surely the existence of an identifier that could be the same regardless of network/cell tower broadcasting the alert would then allow phones to effectively de-dupe the alerts (Dual SIM/Rebooted Phone/etc) easily...

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mentalinc

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#3406507 22-Aug-2025 15:38

Brace yourself for more spam with another earthquake: https://www.stuff.co.nz/world-news/360800453/magnitude-75-earthquake-hits-south-america

Quick math suggests it's still like 8-9 hours away.

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DS248

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#3406521 22-Aug-2025 17:03

mentalinc:

Brace yourself for more spam with another earthquake: https://www.stuff.co.nz/world-news/360800453/magnitude-75-earthquake-hits-south-america

Quick math suggests it's still like 8-9 hours away.

Perhaps leave this to those who know more about earthquakes and tsunamis.

In terms of energy release, Mw 7.5 is almost two orders of magnitude smaller than an Mw 8.8 earthquake
It was a strike-slip earthquake with very little if any chance of generating a large trans-oceanic tsunami
Almost all historical large trans-oceanic tsunamis have been generated by major subduction interface "megathrust" earthquakes such as the recent Mw 8.8 Kamchatka event.

If an emergency tsunami warning message is issued in NZ for this event then there would indeed need to be some serious questions asked.

But ... don't hold your breath waiting for an emergency tsunami warning message for this one.

JimmyH

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#3408680 29-Aug-2025 20:48

RunningMan:

Suggest you learn a little about the energy in a 20-30cm tsunami vs a 20-30cm swell. A tsunami wave rather than being a couple of metres in length (i.e. peak-peak) may be multiple kilometres. That's several orders of magnitude more energy for the same wave height. Don't get fooled into thinking it's like a normal wind blown wave of the same height because it isn't.

Have a read of this for a start. https://www.noaa.gov/jetstream/tsunamis/tsunami-propagation/jetstream-max-tsunamis-vs-wind-waves

Which is interesting, but largely irrelevant to my point. They jumped the gun. They would know hours in advance if there was a huge wave coming, and how big it was likely to be. They knew where the quake was. They knew how long it would take for a wave to reach here. They could and should have waited until they had necessary data from satellites and ground monitoring stations before they made a call. Had they done so they would still have had plenty of time to send an alert if it was actually warranted.

If they keep doing this when there isn't remotely an actual emergency there is a risk that some people will disable the feature on their phones (I'm already thinking of doing so. And yes, there isn't a setting for this. And a bigger risk that many more will just shrug and ignore it alerts, being used to constant cries of "Wolf, wolf, wolf...." from NEMA. So when there's an actual emergency and lives are actually at risk, the alerts will have a lot less impact than they should.

Whoever made the call to send this should, at the very least, get a scathing performance review this year.

halper86

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#3408746 30-Aug-2025 12:28

Some good points bought up here. I myself work on a very low lying peninsula in southern South Island

The emergency alert was complemented by comms from my employer in the form of SMS. Sparked some good conversations in my team about the ‘what if’s’.

Large group of workers (400+ on any given weekday) and one road out. A pretty scary thought, let’s hope the day never comes.

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