Pictures: Giant Sinkhole Pierces Guatemala

Sinkhole Spurred by Storm?

Photograph by Johan Ordonez, AFP/Getty Images

The roughly 30-story-deep sinkhole in Guatemala is seen from street level on May 31, 2010.

Sinkholes are particularly prevalent when heavy rains follow a long period of drought, said Jonathan Martin, a geologist at the University of Florida.

Drought can empty subterranean cavities of water, making them less able to support the overlying soil—flooding only adds to the danger. "If there's a tropical storm and all of a sudden the soil above the cavity is filled with water instead of air, the weight will cause the [sinkhole] to collapse," Martin said.

Published June 1, 2010

Cop Skirts Sinkhole in Guatemala

Photograph by Walter Pena, AFP/Getty Images

A police officer walks by the sinkhole in Guatemala City on May 30, 2010—the day the sinkhole appeared.

It probably isn't safe to venture too close to the chasm, Currens, the hydrogeologist, said. The sinkhole could still grow.

Depending on the makeup of the subsurface layer, the sinkhole in Guatemala "could eventually enlarge and take in more buildings," he said.

(See a Texas sinkhole picture.)

Published June 1, 2010

Sinkhole From Street Level

Photograph by Rodrigo Arias, Reuters

The 2010 sinkhole in Guatemala City (pictured on May 30) is strangely similar to a sinkhole that appeared in Guatemala City in 2007 after a sewer line had ruptured and saturated the surrounding soil with water.

The 2010 sinkhole could have formed in a similar fashion, Currens said. A burst sanitary or storm sewer may have been slowly saturating the surrounding soil for a long time before tropical storm Agatha added to the inundation.

Sinkholes typically appear in places where the subsurface bedrock is made of limestone, said the University of Florida's Martin, because limestone is more easily eroded by water.

(See Guatemala pictures from National Geographic Traveler magazine.)

Published June 1, 2010

Guatemala Sinkhole Seen From Above

Photograph courtesy Paulo Raquec

The 2010 sinkhole in Guatemala (pictured) had likely been forming for several weeks or even years before floodwaters from tropical storm Agatha caused the sinkhole to cave in, the University of Kentcky's Currens said.

"The tropical storm came along and would have dumped even more water in there, and that could have been the final trigger that precipitated the collapse," Currens said.

(Related: "Sinkhole Holds 12,000-Year-Old Clues to Early Americans.")

Published June 1, 2010

2007 Sinkhole in Guatemala

Photograph from Reuters

In 2007 an approximately 30-story-deep sinkhole (pictured) swallowed several homes and killed three people in Guatemala City.

Typically, officials fill in sinkholes with large rocks and other debris. But the 2010 Guatemala sinkhole "is so huge that it's going to take a lot of fill material to fill it," Currens said.

"I don't know what they're going to do."

More: Traveler's overview of recent Guatemala natural disasters >>

Published June 1, 2010