During the recent Japan earthquake, it took just 3 seconds for the closest seismometer to detect P-waves sufficient to signal an alert. How much lead-time (to nearest sec), did the people of Sendai have if the damaging S-waves travel at about 4100 m/s in this region? The focus of the recent Japan earthquake was 132 km from Sendai.
I’m not sure what lead-time is? is it asking for the difference between the P and S wave arrival time?
Chosen Answer:
Well, 4,100 metres/second to cover a distance of 132Km or Kilo metres, or 132,000 metres. So… distance/speed = time.
by: Nicky
on: 15th December 12