Water Damage & Flooded Basement Restoration Services

How Earthquakes Happen

By the RestorationSOS Educational Staff

We've all seen news reports following earthquakes occurring in various corners of the world and we are often amazed at the level of destruction to life and property that results. Most of us, however, are unaware of the science behind the average earthquake, why they happen, and what happens during the quake itself.

Basically, an earthquake occurs whenever two plates of the earth suddenly slip past one another. The surface area where they slip is called a fault or fault plane and the area below the earth's surface where the earthquake starts in referred to as the hypocenter. The same location above the earth's surface is referred to as the epicenter.

Earthquakes cannot be predicted, although some will announce their coming through the occurrence of foreshocks, smaller tremors that occur in advance of the larger quake. Unfortunately, you never know you are dealing with a foreshock until after the major quake has already arrived. Aftershocks may occur in the hours or even days, weeks, or months following the main quake.

What Causes Earthquakes to Start

Earthquakes are caused by various pieces of the earth's four major layers jostling against one another. The inner core, outer core, mantle, and crust are all pieced together like a giant puzzle and they are forever sliding around, which means they occasionally bump one another. When those bumps occur, that triggers the shaking and trembling of the earth known as an earthquake. Because the edges of these pieces are rough, they normally get stuck while the rest of the piece continues moving. When the plate becomes unstuck is the event that manifests itself as an earthquake.

The earth shakes as a result of these movements due to pressure being released from the various plate joints. Once they become unstuck from each other, stored up energy manufactured through the movement of the plates is released, radiating outward from the fault in all directions. This is called a seismic wave and can best be illustrated by throwing a pebble into a pond and watching the ripples move outward. They radiate outward, but become progressively less noticeable as they go. Seismic waves move through the earth, and when they reach the surface, they shake the ground and anything on that ground.

Earthquake intensity may be registered on the Richter Scale and quakes may rate anywhere from 1 to 10, with 10 being the strongest and most destructive. Earthquakes occurring at sea have been known to produce dangerous waves called tsunamis that are capable of racing across the ocean at high speeds, striking land and causing damage and loss of life for miles inland.

Recommended Reading
Preparing for Earthquakes
Staying Safe during Earthquakes