Subject :NSO Class : Class 9
Earthquakes generate sound waves inside the earth.
Unlike a gas, the earth can experience both transverse
S and longitudinal P sound waves. Typically the
speed of S wave is about 4.0 km s-1, and that of P
wave is 8.0 km s-1. A seismograph records P and
S waves from an earthquake. The first P wave arrives
4 minutes before the first S wave. Assuming the
waves travel in straight line, at what distance does
the earthquake occur?
A 960 km
B 640 km
C 1920 km
D 2880 km