The Science of Earthquakes

Learn the science behind this natural disaster.

Image source: https://www.latimes.com/science/story/2023-02-07/what-makes-an-earthquake-deadly-these-are-the-things-that-matter 

Author: Charlotte Leung 

Air-filled with horror, cries echo through your bedroom walls as you step out to feel the intense vibrations beneath your feet. Sirens penetrate through the city, you hide underneath your living room table for safety. For us, this may seem like a hypothetical situation, but for millions around the world, this is an inevitable fear. Earthquakes, often perceived as sudden shaking off the ground, are a horrifying and traumatic event that occurs worldwide. But how does an earthquake actually work?

An earthquake occurs when two tectonic plates suddenly slip past each other; the surface is known as a fault. Tectonic plates are the large sections located in the Earth’s lithosphere, which consists of the crust and the upper mantle; the plates float on the asthenosphere underneath them. These plates can create movement mainly in the following three ways.

  • Convergent boundaries: The collision of plates, leading to the subduction of one plate or the creation of a mountain range.
  • Divergent boundaries: The drifting apart of plates, causing the rise of magma for the formation of a new crust.
  • Transform boundaries: The slip of plates, leading to friction.

When the stress of movement goes past the strength of the rocks, they suddenly shatter or slide along a fault line, causing the release of energy in the form of seismic waves. This is a process called the elastic rebound. Seismic waves then travel through the earth, releasing energy for an earthquake to occur. There are three types of seismic waves:

  • Primary waves – the fastest of the waves and expands the material that comes its way.
  • Secondary waves – moves the material that is perpendicular to its direction, and is slower than the primary waves.
  • Surface waves – moves along the surface of the earth and creates the most destruction.

The waves released are measured by the Richter scale or moment magnitude scale, and the effects on the crust are measured by Modified Mercalli Intensity scale. Most earthquakes occur towards the edges of tectonic plates, in areas like the ring of fire. Following the main shock of the earthquake, aftershocks may occur, which are smaller vibrations following the main shock. They are caused by the adjustment of the crust to the new stresses. Through knowing how earthquakes work, we can properly predict and shield innocent lives from being taken away. With better and better technology, we can further improve things such as the structural integrity of buildings and protocols to ensure minimal destruction.