The sinkhole in Florida is now about 30 feet across and 25 feet deep, as of Friday night.
It’s a troubling scene that experts say could happen here in Hawaii.
That’s because we have one thing in common — limestone.
But, there’s a reason why we don’t have too many limestone sinkholes, like they do in Florida.
Here in Hawaii, we sometimes see holes in the ground, but they’re usually caused by water main breaks — the water eroding the soil, which causes the ground to buckle.
Or, you may remember this from 2005 — four sinkholes at the Kauai Marriott Resort that even swallowed up two cars.
The sinkholes formed after storm water eroded the soil under the hotel’s parking lot.
As for this latest sinkhole in Florida — it had nothing to do with soil eroding.
Professor Steve Martel of the Department of Geology and Geophysics at UH Manoa shows us what happened.
"The rock underneath the house in Florida is limestone," said Professor Martel.
And limestone is a porous rock that easily dissolves in water.
"What will happen is these cracks will widen out, if these things get big enough they start to grow up beneath the surface," said Professor Martel.
And sometimes, the surface just gives way, like what happened Thursday night.
"I was shocked but not surprised because they have sinkholes develop in Florida with some regularity," said Professor Steve Martel.
Here in Hawaii, we don’t have limestone sinkholes regularly like in Florida, but…
"…this whole area in here, a lot of that is underlined by limestone, that big plain, is largely underlined by coral reef limestone," said Professor Steve Martel.
In fact, he says even UH Manoa’s lower campus is built on limestone.
"There was a sinkhole near University and King about a half mile from here, so they have developed here, and the one near University and King was the same size as the one in Florida, maybe even a little bigger," said Professor Steve Martel.
He’s speaking about an incident that happened back in the 1950′s.
"It took part of a parking lot and part of a building," said Professor Steve Martel.
And, he says homes and businesses in Ewa are built on limestone.
When asked if he would you feel safe living on the Ewa plain, or if he’d buy a house there, Professor Martel replied: "I like having a short commute so I like living closer to the university. This is not the sort of thing that would bother me if I were out there, they do happen but there are not that many of them to my knowledge," said Professor Martel.
The difference between here and Florida is that in Florida, they tend to pump out a lot of the groundwater, which creates caverns.
"So we’re not likely to be in as near as a problematic situation as Florida is," said Professor Martel.
And luckily, a lot of the homes and businesses here in Hawaii aren’t built directly on limestone. Rather, there’s a layer of lava rock on top of the limestone, and lava rock doesn’t erode as easily.
See the original article at: KHON2 Local News
