… The Salton Sea’s eastern shore is home to hundreds of mud pots, though only this one—known as the “Niland Geyser,” “moving mud spring,” and “Mundo”— moves. Scientists can’t figure out why: Some think that a series of earthquakes made the bedrock more permeable and allowed the mud to seep through. But there’s no conclusive link. The region’s unique geology certainly plays a role: a highly faulted area with thick sediment that drains from the Grand Canyon through the Colorado River. A number of forces—tectonic activity, the accumulation of gases, the heat of young magma—conspire to force this sediment upward, resulting in puddles that spit and gargle like a witch’s brew. … Seemingly out of nowhere, the muck started moving southwest at a quick clip, at least as far as puddles go, digging a crater of slurry sediment and water 75 feet wide and 25 feet deep.