3 ms·
There have also been at least a couple of strong earthquakes where the system didn’t go off when it was supposed to, so it’s not yet perfect. Obviously, I don'
by goodcanadian 5y ago
There have also been at least a couple of strong earthquakes where the system didn’t go off when it was supposed to, so it’s not yet perfect.
Obviously, I don't know the exact details of those incidents, but if the epicentre is too close to you, there will not be time for the alert to occur. The alerts work because the earthquake travels slower than the telecommunications signals. No alert can be triggered until after an earthquake has occurred. Then, however, a warning can be sent to notify people further away from the epicentre before the shaking reaches them.
- not2b 5y agoYes, the further you are from the epicenter the more time there is for a warning, but it doesn't rely on having a detector right at the center. That's because there are two sets of seismic waves that travel at different speeds. P waves arrive first; S (shear) waves cause most of the damage. Of course, electronic signals travel much faster than either.
- EE84M3i 5y agoIn the large earthquake in Tokyo in October, I felt the P wave, then got the alert on one of my phones, then the s-wave hit and I got the alert on my other phone (different provider). Interesting seeing the race, and I wonder how optimized notification systems are. [1]: https://en.m.wikipedia.org/wiki/2021_Chiba_earthquake https://en.m.wikipedia.org/wiki/2021_Chiba_earthquake