Question

In convergent boundary, plates-
A. Moves towards each other
B. Slide horizontally
C. Pull away each other
D. All of the above

Answer 1

Hint: These plates are also referred to as destructive and colliding plates. 80% of the earthquakes are because of convergent boundaries and the zones where earthquakes happen are subduction zones. Seismic tomography reveals chunks of lithosphere that have been broken off during convergence.

Complete Answer:
OPTION A: Moves towards each other
A convergent boundary is a region on earth where two or more lithospheric plates collide. Collision takes place when both the plates move towards each other and collide head-on, they might even slide beneath each other by a process called Subduction.
- Basically, the subduction zone is a plane where many earthquakes take place. These collisions take place in millions to ten million years and they often result in volcanic eruptions, earthquakes, destruction of lithosphere and contortion.
- As the plates move towards each other, they sometimes get caught and pressure builds up. When the plates finally slip due to increased pressure, energy is released as seismic waves, causing the ground to shake. This is an earthquake.

OPTION B: Slide horizontally
Most seismic activities occur at three types of plate boundaries - Convergent, Transform, Divergent. When two tectonic plates slide past each other horizontally, the place where they meet is a Transform or Lateral fault. The San Andreas Fault is one of the best examples of Lateral plate movement. So, option B stands incorrect.

OPTION C: Pull away each other
The third type of plate boundaries are Divergent or Spreading boundaries. This is the region where two plates move away from each other. The earthquakes that occur along these zones, called spreading centres, are relatively small. The Great Rift Valley in Africa is formed as a result of divergent plate motion. Thus, option C is incorrect.

Hence, option A. Moves towards each other, is the right answer.

Note: Seismic waves are recorded on a Seismometer to detect and record earthquakes. During an earthquake the base moves and the mass does not. There are 3 types of convergent plate boundaries - continent-continent convergence, Ocean-continent convergence and ocean-ocean convergence. The example of convergent boundaries is The Andes mountain range of western South America, between an oceanic and continental plate, here the Nazca plate is subducted beneath the South American plate.