Guatemala City has had experience with sinkholes before: In 2007, three people and a dozen homes here suddenly disappeared into the earth. But no one was prepared for anything like this.
On Sunday, May 30, 2010, an enormous hole, 60 feet wide and 30 stories deep, opened up in the middle of Guatemala City, swallowing a three-story building, a home, and at least 100 people.
Generally, sinkholes are caused by underground rivers or stores of water which erode bedrock and cause the ground above to collapse. Guatemala City is largely built on weak materials such as volcano pumice, however, and as such its sinkholes open extraordinarily quickly, leaving little time for escape.
Most geologists are chalking the new sinkhole's opening up to Tropical Storm Agatha. At least one specialist thinks the sinkhole may have been caused by broken underground pipes gushing water underneath the building, and Guatemalan officials are rushing to find the pipe, stop the leak, and fill in the hole, or else risk the hole widening. But getting construction crews to fill in a hole this large could take years, especially in the slums of Guatemala, where transportation is slow at best.
... 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.
(See Guatemala pictures from National Geographic Traveler magazine.)
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."
This is a previous sinkhole in Guatemala. A 30-story-deep sinkhole appeared in Guatemala City on February 23:
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.
via Photo in the News: Giant Sinkhole Swallows Guatemala Homes.http://xenophilius.wordpress.com/wp-admin/post.php?post=27341&action=edit&message=1
Thursday, June 03, 2010 1:32:09 AM by ANI - Washington, June 03 (ANI): The giant sinkhole in Guatemala City that has caught attention of the world shouldn’t be called a sinkhole, according to an expert.Geologist Sam Bonis claims “sinkholes” mean areas where bedrock is solid but has been eaten away by groundwater.
However, the situation beneath the Republic of Guatemala’s capital, according to Bonis, is far different, and more dangerous.
“Sure, it looks a lot like a sinkhole. And a whale looks a lot like a fish, but calling it one would be very misleading,” Discovery News quoted him, as saying.
He said the term “piping feature” is more appropriate for the 100-foot deep, 66-foot side circular chasm.
Bonis was part of a team of geologists who investigated similar hole that had opened after a sewage pipe broke just a few blocks from the current spot, in 2007.
He said: “Our recommendation was that this could happen again. When you have water flowing from storm water runoff, a sewage pipe, or any kind of strong flow, it eats away at the loose material. We don’t know how long it has to go on before it collapses. But once it starts collapsing, God help us.” (ANI) -