JACKSONVILLE, Fla. --Mary Scott moved into the Sterling Ridge subdivision in 2005.

"It is getting dangerous," she said.

Scott recently discovered several holes, each about four feet deep, in anopen fieldbehind her fence line.

"This was going to be a retention pond, they never built it," she said. "Maybe we have a drainage line running through it I don't know."

Her neighbor Jeff Krych has lived in the community since 1998 and he too has seen the soil shifted over the years.

"I want to say that these [holes] are probably fairly recent," said Krych.

Scott said she isconcerned that behind the now visible holes there's a sinkhole waiting to happen.

"You see a divot there in the middle of the field, that could be a potential sinkhole," said Scott. "It is close to our homes, nobody wants their home to end up in a sinkhole."

The Department of Environmental Protection said sinkholes are a natural component of Florida's landscape and there are several types. A 2004 Geological Survey map shows Duval county is one of the least affected areas in the state.

"Over here it is rare to have a sinkhole," said Gary McCollum. "But it can happen."

McCollum is executive vice president ofCal-Tech testing, a geo-technical engineering firm.

"I understand sensitivity is very high right now with everything that is going on," said McCollum.

He said ares on the First Coast are unlikely to have a sinkholes, conditions like what Scott discovered in her backyard requires more testing.

"If you start seeing changes like loss of soil or depressions get somebody to take a look at it," said McCollum.

Scott has notified City Hall, which is one of the proper steps to take, and the other residents have notifiedtheir homeowners association as well.

"You see how many homes are in this area," said Scott. "I'm not sure what it is butit is threatening all of these homes."

In one of the holes thereappears to be construction debris.

McCollum said his company, Cal-Tech testing, will be glad to investigate the area to determine if residents have to be concerned about a sinkhole.

If there's a sinkhole what's covered by insurance?

David Miller of Brightway insurancesaid standard homeowners insurancecovers catastrophic damage to homes, but Miller said it is smart for every homeowner topurchase a sinkhole rider for more protection.