Featured Research

from universities, journals, and other organizations

Science of sinkholes: 20 percent of U.S. lies in susceptible areas

Date:
March 5, 2013
Source:
U.S. Geological Survey
Summary:
A devastating sinkhole occurred in Florida on Feb. 28, 2013, raising questions and concerns about this incredible phenomenon. Around 20 percent of the United States lies in areas susceptible to sinkhole events, highlighting the need for research and to be informed about this hazard.

Cover-collapse sinkhole in limestone near Frederick, Maryland (September 2003).
Credit: Randall Orndorff, USGS

A devastating sinkhole occurred in Florida on Feb. 28, 2013, raising questions and concerns about this incredible phenomenon. Around 20% of the U.S. lies in areas susceptible to sinkhole events, highlighting the need for research and to be informed about this hazard.

Related Articles


What is a Sinkhole?

A sinkhole is an area of ground that has no natural external surface drainage. Basically this means that when it rains, all of the water stays inside the sinkhole and typically drains into the subsurface.

Sinkholes are most common in what geologists call, "karst terrain." What's that? These are regions where the type of rock below the land surface can naturally be dissolved by groundwater circulating through them. Soluble rocks include salt beds and domes, gypsum, and limestone and other carbonate rock. Florida, for instance, is an area largely underlain by limestone and is highly susceptible to sinkholes.

When water from rainfall moves down through the soil, these types of rock begin to dissolve and spaces and caverns develop underground. Sinkholes are dramatic because the land usually stays intact for a period of time until the underground spaces just get too big. If there is not enough support for the land above the spaces, then a sudden collapse of the land surface can occur.

Keep in mind though that while collapses are more frequent after intense rainstorms, there is some evidence that droughts play a role as well. Areas where water levels have lowered suddenly are more prone to collapse formation.

Areas Most Susceptible

About 20% of our country is underlain by "karst terrain" and is susceptible to a sinkhole event. The most damage from sinkholes tends to occur in Florida, Texas, Alabama, Missouri, Kentucky, Tennessee, and Pennsylvania.

Different Types and Various Severities

Sinkholes can be characterized into two types. First, there are cover-collapse sinkholes, which can develop abruptly (over a period of hours) and cause catastrophic damages. Secondly, there are cover-subsidence sinkholes, which form slowly over time with the ground gradually subsiding or deflating. These types of events can be less noticeable and go undetected for long periods.

Sinkhole collapses can range in size and severity. Sinkholes can vary from a few feet to hundreds of acres and from less than one to more than 100 feet deep. Sinkholes can have dramatic effects, especially in urban settings. They can contaminate water resources and have been seen to swallow up swimming pools, parts of roadways, and even buildings.

Is There a Sinkhole on Your Property?

This is a difficult question, and unfortunately there isn't a very efficient system to determine this quite yet. It is recommended that people constantly observe their property for things such as small holes in the ground or cracks formed in a structure's foundation. People can also check to see if they live in areas underlain by soluble rock, and they can do so by checking with county offices, local or state geological surveys, or the USGS.

Even Humans Cause Sinkholes

While sinkhole collapses are frequent in karst areas, there are a variety of other circumstances that can lead to such events. Many sinkholes form from human activity. Collapses can occur above old mines, from leaky faucets, when sewers give way, or due to groundwater pumping and construction.

Think about all the changes that occur when water-drainage patterns are altered and new systems are developed. And when industrial and runoff-storage ponds are created, the resulting substantial weight of the new material can trigger an underground collapse of supporting material.

Aquifer systems are another example. The sediment above the system is delicately balanced by ground-water fluid pressure, meaning that the water below ground is actually helping to keep the surface soil in place. Groundwater pumping for urban water supply and for irrigation can produce new sinkholes. If pumping results in a lowering of groundwater levels, then underground structures could fail and thus sinkholes can occur.

Start with USGS Science

Starting with science is important to understanding where sinkholes are likely to occur and making the best decisions to protect life and property. Scientists at the U.S. Geological Survey (USGS) play a key role by developing geologic maps of the nation.

By mapping the nation, the USGS contributes important geologic and topographic information needed to understand karst regions and local areas. Detailed geologic mapping helps to define areas of soluble at the surface and in the subsurface, thus educating the land planners, policy makers, and the public about sinkhole risk.

These USGS maps and data are essential to many other purposes, including assessing ground-water quality and contamination risks; predicting earthquake, volcano, and landslide hazards; characterizing energy and mineral resources and their extraction costs; waste repository siting; land management and land-use planning; and general education.

Learn More

Learn more about sinkholes by reading an online overview story (http://ga.water.usgs.gov/edu/sinkholes.html) or a USGS fact sheet (http://pubs.usgs.gov/fs/2007/3060/pdf/FS2007-3060.pdf).

To see a catalog of all geologic maps for the country, visit the USGS National Cooperative Geologic Mapping Program website (http://ncgmp.usgs.gov/). On that site, you can browse through the National Geologic Map database, which includes maps published by the USGS and state geological surveys.


Story Source:

The above story is based on materials provided by U.S. Geological Survey. Note: Materials may be edited for content and length.


Cite This Page:

U.S. Geological Survey. "Science of sinkholes: 20 percent of U.S. lies in susceptible areas." ScienceDaily. ScienceDaily, 5 March 2013. <www.sciencedaily.com/releases/2013/03/130305155755.htm>.
U.S. Geological Survey. (2013, March 5). Science of sinkholes: 20 percent of U.S. lies in susceptible areas. ScienceDaily. Retrieved November 26, 2014 from www.sciencedaily.com/releases/2013/03/130305155755.htm
U.S. Geological Survey. "Science of sinkholes: 20 percent of U.S. lies in susceptible areas." ScienceDaily. www.sciencedaily.com/releases/2013/03/130305155755.htm (accessed November 26, 2014).

Share This


More From ScienceDaily



More Earth & Climate News

Wednesday, November 26, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Bolivian Recycling Initiative Turns Plastic Waste Into School Furniture

Bolivian Recycling Initiative Turns Plastic Waste Into School Furniture

Reuters - Innovations Video Online (Nov. 26, 2014) Innovative recycling project in La Paz separates city waste and converts plastic garbage into school furniture made from 'plastiwood'. Tara Cleary reports. Video provided by Reuters
Powered by NewsLook.com
Antarctic Sea Ice Mystery Thickens... Literally

Antarctic Sea Ice Mystery Thickens... Literally

Newsy (Nov. 25, 2014) Antarctic sea ice isn't only expanding, it's thicker than previously thought, and scientists aren't sure exactly why. Video provided by Newsy
Powered by NewsLook.com
3D Map of Antarctic Sea Ice to Shed Light on Climate Change

3D Map of Antarctic Sea Ice to Shed Light on Climate Change

Reuters - Innovations Video Online (Nov. 24, 2014) A multinational group of scientists have released the first ever detailed, high-resolution 3-D maps of Antarctic sea ice. Using an underwater robot equipped with sonar, the researchers mapped the underside of a massive area of sea ice to gauge the impact of climate change. Ben Gruber reports. Video provided by Reuters
Powered by NewsLook.com
Car Park Solution for Flexible Green Energy

Car Park Solution for Flexible Green Energy

Reuters - Innovations Video Online (Nov. 24, 2014) A British solar power start-up says that by covering millions of existing car park spaces around the UK with flexible solar panels, the country's power problems could be solved. Suzannah Butcher reports. Video provided by Reuters
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins