Which one of the following reasons best explains the occurrence of large number of earthquakes at the active plate boundaries compared to the plate interiors?

Question

Match LIST-I with LIST-II (Seismic Waves):\[\begin{array}{|c|c|} \hline \textbf{LIST-I (Type of seismic wave)} & \textbf{LIST-II (Characteristic of particle motion)} \\ \hline \text{A. Primary Wave} & \text{III. in longitudinal direction} \\ \hline \text{B. Shear Wave} & \text{IV. is perpendicular to the direction of wave propagation} \\ \hline \text{C. Love Wave} & \text{I. in horizontal plane and transverse to the direction of wave propagation} \\ \hline \text{D. Rayleigh Wave} & \text{II. in vertical plane and retrograde} \\ \hline \end{array}\]

Answer 1

Step 1: Where quakes cluster.
Most earthquakes happen along plate edges, while plate interiors stay fairly quiet. We need the main reason for this.

Step 2: How a quake works.
A quake is the sudden release of stored elastic strain. So whichever region builds up the most strain will shake the most.

Step 3: Why edges build more strain.
At plate boundaries the plates push, pull or grind past each other all the time. This constant motion loads up strain that later snaps free as quakes.

Step 4: Test the other options.
Stiffness, heat flow and crust thickness do change near boundaries, but none of them is the main driver of the high quake count. The key driver is the strain build up.

Step 5: Final choice.
So edges shake more because strain energy gathers there.
\[ \boxed{\text{Strain energy accumulation is higher at the plate boundaries}} \]

Which one of the following reasons best explains the occurrence of large number of earthquakes at the active plate boundaries compared to the plate interiors?

Show Hint

The Correct Option is A

Solution and Explanation

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