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Tsunami Warning for Northern California

tsunami.gov

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Re: Tsunami Warning for Northern California

#91

Post by neonate »

psophis wrote: post #81
jboy55 wrote: post #69

From https://www.tsunami.gov/events/PHEB/2024/12/05/24340001/2/WE... TSUNAMI THREAT FORECAST...UPDATED --------------------------------- * THERE IS NO LONGER A TSUNAMI THREAT FROM THIS EARTHQUAKE.

This message is for Hawaii. Edit: Now as of "1154 AM PST Thu Dec 5 2024" the warning is canceled: https://www.tsunami.gov/events/PAAQ/2024/12/05/so1aq0/3/WEAK...

It's unfortunately hard to tell what regions that message is for, or whether it contradicts the other one saying the warning is still in effect: https://www.tsunami.gov/events/PAAQ/2024/12/05/so1aq0/2/WEAK....

It looks like https://tsunami.gov/?p=PHEB/2024/12/05/24340001/2/WEPA40 is the 11:29 PST message saying there is no tsunami warning for "Non-US/Canada Pacific".

And it looks like https://tsunami.gov/?p=PAAQ/2024/12/05/so1aq0/2/WEAK51 is the 11:25 PST message saying there is still a tsunami warning for "AK/BC/US West Coast".

But it's not easy to tell what one's looking at if one doesn't already understand the system, and conditions of "extreme danger" (which is what my phone told me about half an hour ago) are not a good moment to figure these out.

Edit: here we go: https://tsunami.gov/?p=PAAQ/2024/12/05/so1aq0/3/WEAK51 now says "No Tsunami Warning, Advisory, Watch, or Threat" for "AK/BC/US West Coast" as of 11:55 PST.

Re: Tsunami Warning for Northern California

#93

Post by wbl »

teaearlgraycold wrote: post #89
cossatot wrote: post #68

Based on the location and focal mechanism of the earthquake ( https://earthquake.usgs.gov/earthquakes/eventpage/nc75095651... ), this is a strike-slip earthquake on the plate boundary between the Pacific and Gorda/Juan de Fuca plates. Strike-slip earthquakes occur when two plates slide beside each other during an earthquake, usually along a steeply-dipping if not vertical fault. These kinds of earthquakes almost neve…

The system is training me to ignore it already. I’m in SF and we had a flash flood emergency alert. I never heard of or saw any floods. I could believe a street or two might have had a few inches of water at most. But honestly I’d bet against even that. And then there’s this tsunami alert today.

SF topography means some places like the Mission and Dogpatch can have severe floods and the rest be fine.

Re: Tsunami Warning for Northern California

#94

Post by reducesuffering »

erik_seaberg wrote: post #70
adastra22 wrote: post #17

Earlier quoted context omitted.

280 is for sure safe.

The warning went at least as far as the inland side of Fremont, which seemed extreme.

I, as another Eric in Fremont, also seemed bewildered when I got this warning

Re: Tsunami Warning for Northern California

#95

Post by kccqzy »

numpad0 wrote: post #74
quietthrow wrote: post #33

Interesting observation: I am in a circumstance where I am transitioning from an Android phone (Samsung Galaxy) to a iPhone. I observed that android phone alerted me about an earthquake and that I should be ready to feel tremors. To my surprise as I was pondering how this system works - especially wrt to latency - where it alerts me head of time, I then fell small tremors in 2 or 3 seconds after the alert. The tremor…

LTE ETWS/PWS is mandatory feature, iPhones has the same thing. Maybe you've explicitly disabled it, considering (IIUC) US used it for AMBER alerts and had annoyed lots of people at some point. Generally an earthquake warnings are issued by someone always automatically correlating sensors everywhere, USGS and/or NOAA in case with US, and then cellular carriers broadcasting the alert through LTE feature. This does not…

I think OP is describing a different feature. It's not a carrier feature like Amber alerts but an OS feature. Google documents this feature here: https://crisisresponse.google/android-alerts/ I'm fairly certain this is due to some Android-specific code inside GMSCore. It has nothing to do with carriers.

On iOS you have no such thing and you either rely on the carrier alert (there won't always be one) or install an earthquake alert app such as MyShake.

Re: Tsunami Warning for Northern California

#96

Post by tj-teej »

I am riding the Caltrain south, we slowed to a snail's pace and they said it would take 2hr+ to get to Palo Alto (from SF).

A bunch of people got off, and then the conductor comes back on the PA system to say the speed limitation had been limited and "we'll be going back to 79 MPH, hold on to your hats"

Re: Tsunami Warning for Northern California

#97

Post by s1artibartfast »

teaearlgraycold wrote: post #89
cossatot wrote: post #68

Based on the location and focal mechanism of the earthquake ( https://earthquake.usgs.gov/earthquakes/eventpage/nc75095651... ), this is a strike-slip earthquake on the plate boundary between the Pacific and Gorda/Juan de Fuca plates. Strike-slip earthquakes occur when two plates slide beside each other during an earthquake, usually along a steeply-dipping if not vertical fault. These kinds of earthquakes almost neve…

The system is training me to ignore it already. I’m in SF and we had a flash flood emergency alert. I never heard of or saw any floods. I could believe a street or two might have had a few inches of water at most. But honestly I’d bet against even that. And then there’s this tsunami alert today.

It is also unclear to me how someone is supposed to differentiate a real emergency from an "Extreme threat/danger" and what authority they should look to, besides their common sense.

I guess people can go on twitter and read some random posts.

Re: Tsunami Warning for Northern California

#98

Post by mgsouth »

quietthrow wrote: post #33

Interesting observation: I am in a circumstance where I am transitioning from an Android phone (Samsung Galaxy) to a iPhone. I observed that android phone alerted me about an earthquake and that I should be ready to feel tremors. To my surprise as I was pondering how this system works - especially wrt to latency - where it alerts me head of time, I then fell small tremors in 2 or 3 seconds after the alert. The tremor…

It varies, a lot, and depends upon a lot of things. I'm not current on all the current details, but many moons ago was involved in push notification development.

* Notification path. IoS at the time was pretty protective of the user's battery, and had specific services you had to use. I imagine there's special treatment now for emergency communications.

* Phone state. How deeply asleep is it? Are there other background apps frequently contacting the mothership? Multiple apps can get their requests batched together, so as to minimize phone wake-ups. You can also benefit from greedy apps--VoIP apps, for example, might be allowed/figured out a hack to allow frequent check-ins, and the other apps might see a latency benefit.

* Garbage carriers. Hopefully emergency alerts have a separate path, but I've noticed my provider (who shall remain nameless but is a three-letter acronym with an ampersand in the middle) sometimes delays SMS messages by tens of minutes. (TBF, in my case there might also be a phone problem [Android], but since nameless provider forced it on me when they went 4G-only they're still getting the blame.)

In your case, my money would be on the carrier. Pushing a notification to all phones in an area can be taxing, and cheaping out on infrastructure is very much a thing.

For docs, your best bet would be to go to the developer sites and pull up the "thou shalt..." rules, particularly regarding network activity, push notification, and permitted background activities. And yeah, Apple was much more dictatorial, for good reasons.

Re: Tsunami Warning for Northern California

#99

Post by mosdl »

tj-teej wrote: post #96

I am riding the Caltrain south, we slowed to a snail's pace and they said it would take 2hr+ to get to Palo Alto (from SF). A bunch of people got off, and then the conductor comes back on the PA system to say the speed limitation had been limited and "we'll be going back to 79 MPH, hold on to your hats"

First earthquake for the new electric trains probably, I can see why they would be cautious.

Re: Tsunami Warning for Northern California

#100

Post by Rebelgecko »

numpad0 wrote: post #74
quietthrow wrote: post #33

Interesting observation: I am in a circumstance where I am transitioning from an Android phone (Samsung Galaxy) to a iPhone. I observed that android phone alerted me about an earthquake and that I should be ready to feel tremors. To my surprise as I was pondering how this system works - especially wrt to latency - where it alerts me head of time, I then fell small tremors in 2 or 3 seconds after the alert. The tremor…

LTE ETWS/PWS is mandatory feature, iPhones has the same thing. Maybe you've explicitly disabled it, considering (IIUC) US used it for AMBER alerts and had annoyed lots of people at some point. Generally an earthquake warnings are issued by someone always automatically correlating sensors everywhere, USGS and/or NOAA in case with US, and then cellular carriers broadcasting the alert through LTE feature. This does not…

The wireless emergency alerts (like what you see for amber alerts) that go over cell towers have pretty high latency (IIRC on the order of a minute or two for the alert to disseminate). The native Android earthquake alerts are much faster
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