Which of the following statements with reference to L-Wave or Long Wave generated by an earthquake is/are correct ? 1. They follow the Earth's circumference 2. They travel at more or less at a constant rate Select the answer using the code given below :

L-waves, or surface waves (including Love and Rayleigh waves), are generated by the interaction of body waves with surface rocks [3]. Statement 1 is correct because surface waves are confined to the Earth's surface and follow its circumference; due to their slower rate of decay compared to body waves, they can circle the globe multiple times following a large earthquake [2]. Statement 2 is incorrect because surface waves are dispersive, meaning their velocity is not constant but depends on frequency. Lower frequencies typically propagate at higher velocities and penetrate deeper into the Earth. Additionally, their velocity changes as they travel through materials of different densities [3]. Therefore, while they are the slowest seismic waves and arrive last on a seismograph, they do not travel at a constant rate [3].

Sources

1. [1] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 4: Earths Interior > Secondary Waves (S-Waves) > p. 62
2. [3] FUNDAMENTALS OF PHYSICAL GEOGRAPHY, Geography Class XI (NCERT 2025 ed.) > Chapter 2: The Origin and Evolution of the Earth > Earthquake Waves > p. 20
3. [2] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 4: Earths Interior > Secondary Waves (S-Waves) > p. 63