The Salton Sea was hit by a 4.1 magnitude earthquake on May 20 at 8:15 p.m. Five aftershocks ranging from 2.6 to 3.3 magnitude followed over the next few hours. The earthquakes were centered near the southern edge of the Salton Sea and several were felt by the locals who live in the area. The Salton Sea spreads over an area with partially molten rock below the surface. The shifting of the molten rock and numerous fault lines crossing southern California can produce earthquakes, but it’s been around 9,000 years since our last volcanic eruption.