Statement I: Volcanic eruption is accompanied by earthquakes. Statement II: Volcanoes erupt water vapours and dust particles in the atmosphere.

Statement I is true as volcanic eruptions are frequently accompanied by earthquakes. These seismic events are triggered by the movement of magma through the Earth's crust, which creates fractures in surrounding rock and releases elastic strain energy [3]. Earthquake swarms often serve as precursors to eruptions due to this internal pressurization [1]. Statement II is also true; volcanoes emit a variety of materials into the atmosphere, including water vapor, which is often the most abundant gas, and dust particles (volcanic ash) [4]. While both statements are factually correct, Statement II does not explain why volcanic eruptions are accompanied by earthquakes. The seismic activity is caused by mechanical processes like magma ascent and tectonic plate movement [3], rather than the atmospheric emission of water vapor and dust. Therefore, Statement II is not the correct explanation for Statement I.

Sources

1. [1] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 14: Earthquakes > Volcanic Activity > p. 179
2. [3] Environment and Ecology, Majid Hussain (Access publishing 3rd ed.) > Chapter 8: Natural Hazards and Disaster Management > Causes of Volcanic Eruptions > p. 10
3. [2] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 11: Volcanism > 1) Exhalative (Vapour Or Fumes) > p. 142
4. [4] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 11: Volcanism > 11. Volcanism > p. 139