Quote:Mexico earthquake stirs ‘desert tsunami’
Death Valley cave, home to endangered pupfish, saw 4-foot waves from 7.6 shaker.

By Grace Toohey

About five minutes after the magnitude 7.6 earthquake hit near Mexico’s southwest coast Monday, typically calm water deep in a Death Valley National Park cave started sloshing against the surrounding limestone rock.

The reverberations from the earthquake more than 1,500 miles away created what experts have called a “desert tsunami,” which on Monday made waves erupt up to 4 feet high in the cave known as Devils Hole, a pool of water about 10 feet wide, 70 feet long and more than 500 feet deep in Amargosa Valley, Nev.

The water in the partly filled cave has become an “unusual indicator of seismic activity” across the world, with earthquakes across the globe causing the water to splash up Devils Hole, according to the National Park Service website .
A magnitude 6.8 earthquake that also hit Mexico’s southwest coast early Thursday — not far from Monday’s epicenter — did not agitate the water or create any waves in Devils Hole, said Kevin Wilson, a National Park Service aquatic ecologist. Thursday’s earthquake struck outside Aguililla, a small town in the western state of Michoacán, just after 1 a.m. and caused at least two deaths. Two people also died in Monday’s earthquake, also centered in Michoacán, though farther east.

“It depends on the depth, magnitude and location around the world,” Wilson said. He said earthquakes along the Pacific’s “Ring of Fire” that reach at or above a magnitude 7 typically will register in Devils Hole.

Devils Hole is home to the endangered pupfish, a unique breed that can face short-term challenges after the geological phenomenon, technically called a seiche. The waves in the cave stir sediment and splash away the algae growing on a shallow shelf, which the pupfish rely on to feed, and can also smash some pupfish eggs, Wilson said.

But, he said, in the long term the movement from earthquakes helps remove the buildup of organic matter, which over time can suck oxygen from the unique ecosystem.

“This kind of resets the system,” Wilson said. He said the waves Monday lasted about 30 minutes before calming down.
Wilson said it’s rare for the grown pupfish to die in these events but that park rangers will continue to provide supplemental feedings for the fish, which have seen resurgence in its population in recent years.