The correct option is 1 and 3 only.
Explanation
Earthquake waves are fundamentally classified into two categories: Body waves and Surface waves. These waves differ in their origin, velocity, and propagation characteristics.
- Statement 1 is Correct: Body waves are generated due to the release of energy at the focus (hypocenter). These waves travel through the interior of the Earth, interacting with surface rocks to generate a new set of waves called surface waves. Body waves are further divided into P-waves and S-waves.
- Statement 2 is Incorrect: Body waves are faster than surface waves. Among body waves, P-waves move the fastest and are the first to arrive at the surface. Surface waves are the slowest among earthquake waves and are the last to be recorded on a seismograph.
- Statement 3 is Correct: Although surface waves are the slowest, they are the most destructive. They cause displacement of rocks and structural collapse because they possess high amplitude and involve complex horizontal and vertical ground motion. Consequently, they are considered the most damaging waves.
Key Takeaway: There is an inverse relationship between the speed and destructiveness of earthquake waves; P-waves are the fastest but least damaging, while Surface waves are the slowest but most catastrophic.