Which of the following statements relating to tsunami is/are correct? As the tsunamis leave the deep water of the open sea and travel towards shallow water 1. the speed is reduced considerably 2. they attain enormous height 3. they appear as a gentle rise and fall of the sea Select the correct answer using the code given below.

Tsunamis undergo a transformation called 'shoaling' as they move from the deep open ocean to shallow coastal waters. In deep water, tsunamis have extremely long wavelengths and very low amplitudes (often less than one meter), making them appear as a gentle rise and fall that is often imperceptible to ships [4]. However, as the water depth decreases, the speed of the tsunami is reduced considerably because wave velocity is directly proportional to the square root of water depth [5]. Since the total energy flux remains constant, this reduction in speed and wavelength causes the wave energy to pile up, resulting in the waves attaining enormous height, sometimes exceeding 15 to 30 meters [4]. Therefore, while they appear as a gentle rise in the open sea, they lose this characteristic and become towering waves upon reaching shallow water.

Sources

1. [1] Environment and Ecology, Majid Hussain (Access publishing 3rd ed.) > Chapter 8: Natural Hazards and Disaster Management > Characteristics of Tsunami Waves > p. 33
2. [3] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 15: Tsunami > Propagation of The Waves > p. 191
3. [4] INDIA PHYSICAL ENVIRONMENT, Geography Class XI (NCERT 2025 ed.) > Chapter 6: Natural Hazards and Disasters > Tsunami > p. 59
4. [5] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 15: Tsunami > Normal Waves vs Tsunami Waves > p. 192
5. [2] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 15: Tsunami > Normal Waves vs Tsunami Waves > p. 193