Question

The speed of P-waves in granite is ________

(a) 0.5 cm/sec

(b) 0.5 km/sec

(c) 1.8 cm/sec

(d) 1.8 km/sec

The question was posed to me in an international level competition.

This intriguing question originated from Earthquake Terminology and Seismic Effects on Buildings topic in section Earthquake Resistant Buildings of Construction & Building Materials

Answer 1

Correct answer is (d) 1.8 km/sec

For explanation: P-waves stand for Primary Waves and S-waves stand for Secondary Waves. The speed of P-waves in granite is 1.8 km/sec while the speed of S-waves in granite in 3.0 km/sec.