Let the gods have mercy in 2021
Continuing the discussion from Earthquakes 2020
How does the system detect an earthquake coming 10 seconds before itâs physically felt?
The signal from the sensors arrive nearly instantly, while the seismic waves travel at âslowerâ speeds (+6 km/s).
Earthquake waves travel slower than electric signals. So, if the quake epicenter is far from us but the sensors are close to it, the information âa quake happenedâ can reach us very fast, a bit before the quake waves arrive.
Central Weather BureauâŠthe same guys that told us weâre in for a dry winter. 
Couple of examples, from Mexico. Note the time between the alarm and the actual quake.
Small shake in taipei
Temblor in Taipei.
Got warning. In mrt. Felt nothing.
I was in the wrong year
Ilan again
Was that 20 seconds?
Just a few shakes. No big dealâŠunless that was the foreshock.
I felt a slight wobble. No unusual for Saturday evenings, though.
That was weird. I heard it but didnât really feel much. In Shilin.
Quake in Taipei
Wasnât even one. Felt it and got the warning just after
It was a big jolt in the Taoyuan area followed by ten seconds or so of mild shaking. Very noisy, though.
Sounds bigger than Taipei. Wonder where the epicenter was.
Northeast