With reference to earthquakes, which of the following statements are c

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.

1 and 2 only
1, 2 and 3
2 and 3 only
1 and 4
This question was previously asked in
UPSC CDS-2 – 2016
Statements 1, 2, and 3 correctly describe aspects of earthquakes. Statement 4 is incorrect.
1. Earthquakes are indeed largely concentrated along plate boundaries, especially convergent (subduction and collision zones) and transform boundaries, where tectonic stresses are highest.
2. The focus (or hypocentre) is the exact point within the Earth’s lithosphere where the seismic rupture originates.
3. The intensity of ground shaking and damage caused by an earthquake typically decreases as distance from the epicentre (the point on the surface directly above the focus) increases, as seismic waves lose energy as they travel.
4. Earthquakes occur in both continental and oceanic lithosphere. The epicentre can be located anywhere on the Earth’s surface, including over oceans (e.g., associated with mid-ocean ridges, oceanic trenches, or transform faults in oceanic crust).
The magnitude of an earthquake (e.g., on the Richter or Moment Magnitude scale) measures the energy released at the source, while intensity (e.g., on the Modified Mercalli scale) measures the effect of the earthquake on people, buildings, and the environment at a particular location.