Scientists say filling the giant Guatemala sinkhole isn't as simple as just dumping in gravel and dirt. First, geologists have to understand the conditions that caused it.
The giant sinkhole that opened up in Guatemala City Sunday has geologists scratching their heads and observers calling for better safety controls, but the more pressing issue: What do you do with a sinkhole?
Do you fill it? Will it get bigger? What caused it?
With smaller sinkholes often found in yards after rains, or as the result of digging, experts recommend dropping a concrete slab, gravel, or other solid material to the bottom of the hole, filling with clay-like soil, and finishing with topsoil. The material will usually settle, and it may be necessary to add more soil over time.
But Guatemala's sinkhole is on an exploded scale, and the geological makeup of the region makes predicting the cause and any effective remedies difficult.
The country has some experience with large sinkholes, as it turns out. In 2007, a 330-foot-deep sinkhole opened up in Barrio San Antonio, just 15 blocks away from the current one in Ciudad Nueva. That sinkhole is thought to have been caused by a broken storm drain pipe that over time weakened and washed away the ground above it.
The burst water pipe theory makes sense to Mr. Currens. "Any conduit carrying water is always an exacerbative or causative factor," he says.