The Japanese Meteorological Agency is starting up a new early warming system for earthquakes at the start of October - of course earthquakes are not meteorological, but they are covered by the "natural disaster" remit. Shame foreigners aren't, but that's another story.
According to what I've read, the basic idea seems to be that they hope to detect the initial "p-wave" tremors (the primary pressure wave which travels fast), and warn before the main s-wave (secondary transverse wave which travels slower) hits. OTOH this page talks about a third type of "surface waves" which are slower still and cause the most damage. Anyway, with a speed of something like 4km/sec, it will be challenging to get any warning out in the area close to the epicentre (where the damage will be focussed) early enough to matter. But even a few seconds may be enough for people to duck under their desks. I just hope there won't be too many false alarms, or people will simply ignore them. We are regularly amused by the warnings of heavy rain over the loudspeakers in the street, that we can barely hear over the noise of the rain that is already thundering down :-) To be fair they do sometimes beat the storm.
The Shinkansen has had an automated system like this in operation for some time. Even if the train doesn't have time to stop, any slowing down can only help. The one time there was a derailment, in Niigata 2004, there still weren't any injuries.
According to what I've read, the basic idea seems to be that they hope to detect the initial "p-wave" tremors (the primary pressure wave which travels fast), and warn before the main s-wave (secondary transverse wave which travels slower) hits. OTOH this page talks about a third type of "surface waves" which are slower still and cause the most damage. Anyway, with a speed of something like 4km/sec, it will be challenging to get any warning out in the area close to the epicentre (where the damage will be focussed) early enough to matter. But even a few seconds may be enough for people to duck under their desks. I just hope there won't be too many false alarms, or people will simply ignore them. We are regularly amused by the warnings of heavy rain over the loudspeakers in the street, that we can barely hear over the noise of the rain that is already thundering down :-) To be fair they do sometimes beat the storm.
The Shinkansen has had an automated system like this in operation for some time. Even if the train doesn't have time to stop, any slowing down can only help. The one time there was a derailment, in Niigata 2004, there still weren't any injuries.
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