The science behind an earthquake

SANTA BARBARA, Calif. - California residents are no strangers to earthquakes but what is the science behind these destructive jolts of energy?

First, let's start with the way we measure the size of an earthquake, which is known as magnitude and is the number most commonly associated with reports of earthquakes. The Richter Scale is a logarithmic scale of numbers, with each whole number representing a 10-fold increase in the amplitude of waves measured on a seismogram, according to the United States Geological Survey (USGS). The categories range from minor to major and the scale starts at zero and ends at a 10. The energy released by an earthquake and intensity of shaking often correlate with magnitude, but the USGS notes that several other factors determine how strong an earthquake feels at the surface. Those factors include the local geology, depth of the earthquake, and proximity to the epicenter.

You may be aware of fault lines, which are fractures in the Earth's crust that allows two segments of rock to move past each other. When these segments move rapidly, an earthquake is caused. There are three types of fault lines: normal, reverse and strike-slip faults.

The USGS states the difference between the type of faults can influence how a person feels the shaking. For instance, a strike-slip fault occurs when horizontal movement is detected and may feel a side to side shift, where a normal and reverse fault, we measure the vertical movement of the ground. This may feel like an up and down motion as the shakes travel outward from the origin point. There are multiple large and small fault lines located throughout California. Earthquake safety is imperative as predictions can come only a few seconds before.

The 1925 Santa Barbara earthquake was a 6.3-6.8 magnitude earthquake that killed 13 people and destroyed large sections of the city. For a list of the largest earthquakes in California since 1900, click here.