A sinkhole has formed on the North Lawn of the White House, and predictably, the temptation was too great for many on social media, who filled the void with all the “drain the swamp” jokes and metaphors one could imagine.

But forget the obvious political jabs and the fact that President Trump uses that phrase as a rallying cry about eliminating corruption in Washington: The saying has some geological merit.

There is a “legitimate swamp” around the White House, Jess Phoenix, a volcanologist, geologist and a Democrat running for a congressional seat in California, said on Tuesday.

Ms. Phoenix said that while sinkholes often form in regions with precarious bedrock like limestone, such as in Texas and Florida, the geology in Washington is different but still susceptible, particularly given the substantial amount of recent rainfall. “It’s all river deposits,” she said.