Sinkhole Swallows Pond: Californian Finds Empty Hole on Property

A giant sinkhole swallowed up the pond on a California couple's property, leaving homeowner Mark Korb stunned when he woke up Sunday morning.

"This looks like the moon," Korb told NBC affiliate KCRA.com.

The sinkhole emptied the pond on Korb's property in Newcastle in about four or five hours, he said. Last time Korb drained it with a pump, it took him seven days.

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Now, Korb is trying to find out what exactly caused the void. Sierra College Professor of Geology Alex Amigo said it appears that rainwater dissolving the ground was not the cause in this instance.

"There was such a lot of mining activity going on in this area in the past, that we never know when there was a man-made cavity underground," Amigo told KCRA.com.

This is just the latest in a string of sinkholes giving way throughout the country. On Feb. 28, a 100-foot-wide sinkhole collapsed the floor of Jeff Bush's bedroom in his Tampa-area home. Though his brother jumped into the wreckage to try and help Bush out, he was ultimately declared dead.

A week later, a second hole opened up just two miles from Bush's Florida house. The 10-foot-wide sinkhole crumbled the ground beneath a fence dividing two properties, and no injuries were reported.

In March, a 40-foot-wide sinkhole collapsed the driveway of a Pennsylvania home, forcing a woman, her daughter, and granddaughter to evacuate.

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Sinkholes are most common in Florida, Texas, Alabama, Missouri, Kentucky, Tennessee, and Pennsylvania, according to the U.S. Geological Survey. The ground beneath these states is composed primarily of easily dissolved rocks like limestone, which gets eaten away by acidic groundwater, causing collapses and voids.