A preliminary magnitude-3.4 earthquake was reported Tuesday morning southwest of Redlands. Shaking from the earthquake at 9:36 a.m. in the San Bernardino County community was reported in the Riverside area.

Understanding Earthquakes

Whether you feel shaking from an earthquake largely depends on three major factors — magnitude, distance, and local soil conditions. Magnitude refers to the strength of the quake. The closer your location to the epicenter, the more likely you’ll feel the effects of seismic waves that become less intense as they move out from the fault. Generally, the looser the soil under your location, the greater the amplification.

Some earthquakes are followed by a larger earthquake, in which case the first quake would then be called a foreshock. For example, the magnitude-9.1 Japan earthquake and tsunami in 2011 was preceded by a magnitude-7.3 foreshock two days earlier.

Aftershocks decrease over time, but can continue for days, weeks, months, and years.

Original reporting: NBC4 Los Angeles — read the source article.