Sinkhole threatens Tampa-area homes
Tuesday, July 22, 2014, 11:59 AM - A huge sinkhole that opened up in Spring Hill, Florida over the weekend continues to threaten several Tampa-area homes.
Officials say the sinkhole is about 30 feet deep and 40 feet wide and prompted the homeowner in Spring Hill to pack her stuff and leave after her home was deemed unsafe.
Officials haven't determined the exact cause of the sinkhole, but a private contractor suspects heavy rain over the weekend may have played a role.
While no injuries have been reported, further evacuations of nearby homes may be required.
This all comes just one year after a similar sinkhole swallowed a Tampa man while he was sleeping.
Jeff Bush died last March and officials say his body was never recovered.
IS CANADA AT RISK OF CATASTROPHIC SINKHOLES?
While catastrophic sinkholes are much less frequent in Canada, there are some sinkhole hazards in a few areas across the country.
"In Canada, sinkholes develop on limestone and more frequently on gypsum, which is comparatively rare, but there is some in Nova Scotia and southwestern Ontario and a few patches elsewhere," says Derek Ford, a retired professor of physical geography and geology at McMaster University in Hamilton, Ontario.
He says a couple of problems have also arisen in Montreal, as well as suburban areas of Winnipeg, the front ranges of the Rockies and in parts of British Columbia, particularly on Vancouver Island.
"We've seen quite a lot of recent collapses up in the Northwest Territories as well as global warming is starting to melt the permafrost there."
According to Ford, hazard can arise in inhabited areas of southern Canada when aquifers are over pumped.
"That's the cause of much of the problems in Florida too," he adds.
In comparison however, the risk of large sinkholes across Canada is much lower.
"In Florida, the rocks are quite young. The limestone rocks form in tropical regions and it's a long time since Canada was cruising in the tropics, so our rocks are older and much harder."
Ford says the rocks are likely to suffer during periods of glaciation, when the glaciers are receding and tremendous quantities of melt water have been poured into the ground.
Experts warn that aside from studying the geology and avoiding hazardous areas to build, there aren't many warning signs that a sinkhole will occur.
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"Unless you put seismologists or recording instruments into the ground to hear the thump of rocks fall 20-30 metres below the surface, there really isn't much you can do," says Ford. "Simply put, just don't build your home on gypsum."
He adds that if you get a small sinkhole developing on your property, which can be more common in Canada, be sure to fill them in right away and don't pump too hard underneath.