Question map
With reference to earthquakes, which of the following statements are correct? 1. Earthquakes largely occur along the converging plate boundaries. 2. Point of origin of earthquake in lithosphere is known as focus/ hypocentre. 3. Intensity of earthquake decreases with distance from the epicentre. 4. Epicentre of earthquake always remains over continents only. Select the correct answer using the code given below.
Explanation
Earthquakes are primarily concentrated along plate boundaries, particularly convergent (subduction) zones where intense geologic processes like crustal deformation occur [3]. The point of origin within the lithosphere where the rupture begins is termed the focus or hypocentre [7]. The point on the Earth's surface directly above this focus is the epicentre [7]. Seismic intensity is highest at the epicentre and naturally decreases with distance due to attenuation, similar to ripples in water [7]. Statement 4 is incorrect because epicentres are not restricted to continents; they frequently occur in oceanic regions, such as along the Mid-Atlantic Ridge (divergent) or oceanic trenches (convergent) [5]. For instance, the Pacific Ring of Fire and subduction zones involve oceanic plates where epicentres are located underwater [5]. Therefore, statements 1, 2, and 3 are correct.
Sources
- [2] Environment and Ecology, Majid Hussain (Access publishing 3rd ed.) > Chapter 8: Natural Hazards and Disaster Management > convergent plate Boundaries and the nepal quake > p. 26
- [3] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 8: Convergent Boundary > Earthquakes > p. 124
- [1] Geography of India ,Majid Husain, (McGrawHill 9th ed.) > Chapter 17: Contemporary Issues > Earthquakes > p. 8
- [7] https://www.usgs.gov/glossary/earthquake-hazards-program
- [4] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 8: Convergent Boundary > 8.2. Continent-Ocean (C-O) Convergence or The Cordilleran Convergence > p. 116
- [5] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 14: Earthquakes > Plate Tectonics > p. 178