Sinkhole in Guatemala: Giant Could Get Even Bigger

[NEP]

A roughly 30-story-deep sinkhole appeared Sunday in Guatemala City.

Ker Than
for National Geographic News
Published June 1, 2010

A huge sinkhole in Guatemala City (map), Guatemala, crashed into being on Sunday, reportedly swallowing a three-story building—and echoing a similar, 2007 sinkhole in Guatemala.

The sinkhole has likely been weeks or even years in the making—floodwaters from tropical storm Agatha caused the sinkhole to finally collapse, scientists say.

The sinkhole appears to be about 60 feet (18 meters) wide and about 30 stories deep, said James Currens, a hydrogeologist at the University of Kentucky.

Sinkholes are natural depressions that can form when water-saturated soil and other particles become too heavy and cause the roofs of existing voids in the soil to collapse.

Another way sinkholes can form is if water enlarges a natural fracture in a limestone bedrock layer. As the crack gets bigger, the topsoil gently slumps, eventually leaving behind a sinkhole.

It's unclear which mechanism is behind the 2010 Guatemala sinkhole, but in either case the final collapse can be sudden, Currens said.

2010 Guatemala Sinkhole Could Grow

A ruptured sewer line is thought to have caused the sinkhole that appeared in Guatemala City in 2007.

The 2010 Guatemala 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.

"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.

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

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."

source: http://news.nationalgeographic.com/n...world-science/

[NEP]

Nghe tin này và thấy hình hôm chủ nhật nhưng nhìn hình tưởng là photoshop, hôm nay thấy có nhiều tờ báo lớn cũng đăng tin này cho nên mới tin là không phải photoshop.

[NEP]

Năm 2007 ở thành phố này cũng bị một lần như vậy...

A 30-story-deep sinkhole appeared in Guatemala City on February 23.

Ted Chamberlain
National Geographic News
February 26, 2007

After rumbling for weeks, part of a poor Guatemala City neighborhood plummeted some 30 stories into the Earth on Friday.

The reportedly 330-foot-deep (100-meter-deep) sinkhole swallowed about a dozen homes and is so far blamed in the deaths of three people—two teenagers, found floating in torrent of sewage, and their father, who was pulled from the chasm.

Rainstorms and a ruptured sewer main may have caused the sinkhole, officials in Guatemala told the Associated Press. After the collapse, the seemingly bottomless depths gave off tremors, sounds of flowing water, and the scent of sewage.

Sinkholes can occur when underground rocks that can be dissolved by water—such as salt, gypsum, and limestone—are inundated. The removal of groundwater can also leave gaps underground that can lead to sinkholes.

While the cause of the Guatemala City abyss remains uncertain, it's effects are undeniable.

Police established a 500-yard (457-meter) no-go zone around the sinkhole, and nearly a thousand people were forced to evacuate—some perhaps forever.

"Last night a friend had to take my handicapped wife out on motorcycle," 15-year resident Antonio Fuentes, 50, told the Associated Press. "Now I'm leaving for good, never to come back."