The Nixa sinkhole - Part II

From what I've been reading online, it seems like the Nixa sinkhole is going to be filled, as it has been declared a "hazardous property" by the City of Nixa. From what I know and have heard, there seems to be little interest in discerning what caused the problem. Instead, the city wishes to solve the problem by an expedient method, keeping the cost below $100,000 total.

For the moment, all seems to be quiet on that front. Is there a cave below? Could it, if it were a cave below the sinkhole, reactivate? In 1977, a Pennsyvanian-age structure actually collapsed in the vicinity of Rainbow Drive in Jefferson City, Missouri, an event described by Jerry Vineyard, former deputy director of the Misssouri State Geological Survey in the book Geologic Wonders and Curiosities of Missouri. This sink was referred to as a "reactivated sink" Is the same in store for Nixa? We'll have to wait and watch.

For those of you who love pictures, I thought that I'd definitely show you more , taken from the air, and supplied from the website of KY-3 television in Springfield.

The photo on the left shows the subdivision that the sinkhole is in, and the one on the right shows an attempt to monitor the sinkhole from the end of a fire department "snorkel" truck. As of today, the sinkhole is now 80 feet in diameter. Will it continue to enlarge? With rain in the forecast, I'd say that enlargement will be a strong probability.

Until next time,

Trenchless Geologist

The Nixa Sinkhole

Little did I know that last month's post on sinkholes would be so timely. Here in Missouri, there was a collapse in the town of Nixa, in southwest Missouri. I know most of the principals involved by name, reputation, or from what the 'grapevine' tells me. First off, a series of pictures of the house that was partially destroyed, that dropped into a sinkhole 75 feet deep.

Lost in the sinkhole was the resident's garage and his Chevy Cavalier.

One of the first responders to the scene was the Nixa Fire Department. Rightly, they cordoned off the area. Geologists and other experts came to the scene at the request of the City Administrator, who also happens to be a geology graduate of Missouri State University (formerly known as Southwest Missouri State University).

There's a lot of concern right now about where the material went that was displaced when the sinkhole collapsed. Where did it go? What kind of process is being initiated here? Did the red clayey material (about 35-45 feet in thickness in other areas close to the the sink) drop into a cavern below? Is there a large cavity underneath the area, or are the residents dealing with piping of material down a joint; with a sudden loss of support in either case?

What needs to be done?

So far, there are ideas and hypotheses but little hard evidence other than the visual evidence of the sinkhole, geophysical data from resistivity measurements completed by a crew led by Mr. Peter Price of the Missouri Department of Natural Resources Division of Geological Survey, and seismic measurements that were taken by a crew led by Dr. Neil Anderson of the University of Missouri-Rolla. Dr. Doug Gouzie of Missouri State University, a karst specialist, has also weighed in with his opinions and observations. I also understand that drill holes have been completed at a "safe" distance from the sinkhole, completed to bedrock.

Response to such a catastrophe is initially a "hit-and-miss" proposition. I think that's what probably happened here. As more data is obtained, recorded, and correlated, a strategy may emerge that may protect the residents of Nixa from future collapse.

I wish all of the principals involved well with their studies. I sincerely hope they'll keep me posted as they find out more of the details, and I'll share them with you here.

Until next time,

Trenchless Geologist