Statement I : El Nino is a temperature rising phenomenon over the Pacific Ocean and usually causes dry mon- soon in South Asia. Statement II. : Tsunamis are usually not noticed as the massive ocean waves move silently but assume destructive form as these travel through shallow waters of continental shelves.

Statement I is true as El Niño is characterized by the warming of sea surface temperatures in the central and eastern equatorial Pacific Ocean [c1][t5]. This phenomenon shifts the Walker Cell, leading to descending air over South Asia, which typically results in weaker trade winds and a deficient or dry monsoon over the Indian subcontinent [c1][c5][t7]. Statement II is also true; in the deep ocean, tsunamis have very small amplitudes (often less than a meter) and long wavelengths, making them nearly unnoticeable to ships [t3][t6]. However, as they reach the shallow waters of continental shelves, their speed decreases and their amplitude increases significantly through a process called shoaling, becoming highly destructive [t2][t3][t6]. While both statements are scientifically accurate, Statement II (geological/oceanic wave dynamics) does not explain Statement I (atmospheric-oceanic oscillation), making option 2 the correct choice.

Sources

1. [1] Geography of India ,Majid Husain, (McGrawHill 9th ed.) > Chapter 4: Climate of India > Possible Causes of El-Nino > p. 13
2. [2] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 29: El Nino, La Nina & El Nino Modoki > 29.3. Impact of El Nino on Indian Monsoons > p. 415
3. [3] https://www.usgs.gov/centers/pcmsc/life-tsunami
4. [4] https://education.nationalgeographic.org/resource/el-nino/