Geologist is camped 6,474 meter (about 4 miles) from a volcano as it erupts.
(a) Find how much time elapses before the geologist hears the sound from the eruption? (Suppose the air temperature is 20°C.)
(b) Find how much time does it take the seismic waves produced by the eruption to reach the geologist's camp, assuming the waves travel along the surface through granite as sound waves do? (Suppose the granite temperature is 20°C.)