Guatemala Sinkhole, May 2010
A sinkhole is a natural depression or hole in the earth’s surface caused by the dissolving of carbonate rock. Sinkholes can vary in size from less than 3 ft to 980 ft both in diameter and depth, and vary in form from soil-lined bowls to bedrock-edged chasms. They may be formed gradually or suddenly, and are found worldwide.
Sinkholes are common where the rock below the land surface is dissolved by circulating ground water. As the rock dissolves, spaces and caverns develop underground. These sinkholes can be dramatic because the surface land usually stays intact until there is not enough support. Then, a sudden collapse of the land surface can occur.
Sinkholes can be human-induced, and new sinkholes have been correlated to land-use practices, especially, from ground-water pumping, construction, and development practices. They can also form when natural water-drainage patterns are changed and new water-diversion systems are developed. Some sinkholes form when the land surface is changed, such as when industrial and runoff-storage ponds are created; the substantial weight of the new material can trigger an underground collapse of supporting material, thus, causing a sinkhole.
On Feb 24, 2007, the press reported a 330-foot-deep sinkhole had suddenly appeared, killing three people and swallowing a dozen homes in Guatemala City. This event forced the evacuation of nearly 1,000 people in a crowded neighborhood. Officials blamed the sinkhole on recent rains and an underground sewage flow from a ruptured main. The 100m-deep hole opened in one of the city’s poorest and most overpopulated areas.
“The shaking of the house woke us up,” said 26-year old Edward Ramirez, who lives 50 metres (50 yards) from the sinkhole and said residents had been hearing noises and feeling tremors for about a month. “People were shouting ‘the electric posts are falling down!’ We are going to a friend’s house now, there’s no way we’ll stay here.”
Guatemala was once again struck by tragedy at the end of May 2010, after twin natural disasters. On May 27, the Payaca Volcano, only 19 miles away, erupted, spewing lava, black sand, rock and ash everywhere. A news reporter covering the event close to the volcano was killed by flying debris.
Only two days later on May 29, tropical storm ‘Agatha’ struck, destroying homes, causing floods, and leaving thousands of people displaced. This poverty-stricken country is truly ill-equipped to handle such a double blow. Official figures have given estimates that 30,000 people are now refugees as around 120,000 had been evacuated, and the death toll was at 93 persons and rising.
Added to this trauma on the morning of May 31st was yet another disaster, as a spontaneous sinkhole, 60ft deep and 50ft wide, appeared in Guatemala City after an overwhelming saturation of rains from the tropical storm two days earlier. Local press reported that it swallowed an entire three-story building. A break in the over-stressed sewage pipes after the storm was the cause for this one. There are rumors of other sinkholes now forming nearby.
There was no loss of life on this occasion, but when you see the utter destruction that these events cause, you tend to tread more lightly, wherever you are walking. Who knows, after all, just how stable the ground beneath your feet really is?