Which of the following statements regarding earthquakes is/are correct ? 1. The point on the Earth's surface directly above the focus is called the epicentre of the earthquake. 2. Earthquakes generate Primary and Secondary waves that radiate outward from the earthquake focus. 3. Deep-focus earthquakes are likely to cause more damage than shallow-focus earthquakes. Select the answer using the code given below :

The correct answer is B, 1 and 2 only. The focus, or hypocentre, is the point inside the Earth where the rocks first break and energy is released. The point on the surface directly above it is the epicentre, which is usually where shaking is felt first and strongest, so statement 1 is correct. From the focus, body waves travel outward in all directions: Primary (P) waves, which are the fastest and pass through solids, liquids and gases, and Secondary (S) waves, which are slower and pass only through solids. So statement 2 is correct too. Statement 3 is wrong: the deeper the focus, the more the waves weaken before they reach the surface, so shallow-focus earthquakes, within about 70 km of the surface, usually do much more damage than deep-focus ones. Option A is wrong because it leaves out the true statement 2. Option C is wrong because it includes the false statement 3 and leaves out statement 1. Option D is wrong because statement 3 is false. Exam tip: focus inside, epicentre above it; P waves fastest, S waves only through solids; shallow quakes are the most destructive.