There are about a half-million earthquakes that rock the Earth each day. Most are too small to be felt and most of those that can be felt aren’t strong enough to cause damage. However, there are some that are very large and can shake buildings and structures so badly that they collapse or become unsafe to occupy.
The most destructive earthquakes occur at faults along the boundary between tectonic plates. When the plates get stuck to each other, they build up elastic energy. When this energy overcomes the friction, the plates jiggle rapidly back and forth. The sudden movement releases the energy in vibrations that people feel, and the plates move apart again.
Scientists can’t predict when and where a large earthquake will happen. But they can monitor movements of the Earth’s crust with seismographs. The type of shaking and how severe it will be depends on three things: the magnitude, your distance from the fault, and local soil conditions. The shaking from a fault is more intense nearer to the fault, and certain types of soil amplify (or increase) the seismic waves that cause it.
It’s important to know how to prepare for an earthquake, including knowing where your gas, electric and water shutoffs are and making sure older members of your family can turn them off if needed. It’s also a good idea to practice Drop, Cover and Hold On. And remember that you can get seconds to tens of seconds of warning before an earthquake hits by taking advantage of early warning systems.
