The Foundation Crack Bible - Foundation Cracks, Leans, Bulges, Settlement: Inspecting Foundations for Structural Defects - Detection, Diagnosis, Cause, Repair
InspectAPedia® -
Visual inspection of foundations
Types of foundation damage
Extent of foundation damage
Concrete foundation cracks, damage
Masonry block foundation cracks, damage
Stone foundation bulges & movement
Photographs of foundation crack patterns
Questions & answers on how to evaluate, diagnose, & repair foundation cracks, leans, bulges, movement, damage
This article series describes in detail how to recognize, diagnose & repair various types of foundation failure or damage, such as
foundation cracks, masonry foundation crack patterns, and moving, leaning, bulging, or bowing building foundation walls.
InspectAPedia tolerates no conflicts of interest. We have no relationship with advertisers nor with topics or services discussed at this website.
Types of foundation cracks, crack patterns, differences in the meaning of cracks in different foundation materials, site conditions, building history,
and other evidence of building movement and damage are described to
assist in recognizing foundation defects and to help the inspector separate cosmetic or low-risk conditions from
those likely to be important and potentially costly to repair.
The photo at page top shows a bowed masonry block foundation wall with horizontal cracking that occurred due to earth loading at the time
of construction, probably by vehicles driving too close to the foundation wall shortly after it was constructed. At this website
we explain how it is sometimes possible to be confident about the cause of foundation damage which in turn helps assess
the risk presented to the building.
Photographs of types of foundation cracks and other foundation damage: we have a large library of photographs which
are constantly adding this website. Contact us if you have questions, suggestions, or content contributions for this material. We are pleased to give full citation credit for technical reviewers and content contributions.
Methods & Procedures for Evaluating Residential Structural Foundation Cracks, Movement, & Condition
This document is for building owners, professional or licensed home inspectors, foundation repair companies, foundation engineers, architects,
and other building professionals concerned with residential property
masonry foundation failure detection, diagnosis, and repair.
To be used properly, this information must be combined with specific
on-site observations at the particular building in order to form a reliable opinion about the condition of that building's foundation. Anyone having
concern regarding the structural stability, safety, or damage of a building, foundation or other components, should consult a qualified expert.
The photo above shows a cracked, bulged, leaning stone foundation wall at the edge of an embankment - a condition we discuss further
at this website.
Foundation Inspection Objectives
Home inspectors, building code compliance inspectors, and general building contractors are often able
to recognize possible foundation or other building problems which may be costly or dangerous,
thus requiring the intervention of an expert
foundation repair company or foundation design engineer.
These early visitors to a building site, most often the home inspector,
see a very large number of in-service field conditions leading to building failures.
Foundation inspectors can,
without performing any engineering calculations or analysis,
learn to recognize signs of important foundation or other structural problems developing well before
forensic engineers and foundation experts are asked to
design a repair and almost always well before the actual occurrence of a catastrophic building failure.
This breadth of field inspection experience and education, combined
with an informed and careful building inspection, provide a valuable
first line of defense for building owners and occupants who may be facing previously unrecognized costly or
dangerous foundation damage.
Foundation inspections are conducted to identify & document potential costly or dangerous conditions. The inspection
must consider many factors beyond the obviously visible condition of the foundation, such as attending to site conditions,
evidence of the history of building movement, and the type, location, and extent of cracking and movement.
This data, combined
with education and experience, permit a knowledgeable foundation inspector to advise the client about the urgency of
foundation repair and the type of repair that may be needed.
Accountability: the inspector is accountable for visible portions of the foundation
and for recognizing signs of defects. In some circumstances this may include
invisible or hard-to-see conditions for which there are nonetheless adequate clues: contextual, historical,
or other visible secondary evidence.
Action: If appropriate, the inspector may suggest further evaluation/repair including invasive methods such as removing finish
materials that cover the foundation, outside excavation, the employment of a foundation engineer, foundation repair company,
a test firm to make soil borings, or other investigative measures.
Dangers: Since certain masonry structure defects, such as bulged above ground brick masonry walls, can lead to sudden
precipitous and catastrophic collapse, dangerous conditions may be present at some properties.
While there are often
hidden conditions which can disguise building conditions, the ability to
recognize those potentially urgent or dangerous conditions which can be detected is important in a foundation inspection.
Note: In-service field conditions refers to the state of repair of a building or its components
while the building is in-use. Building construction standards, engineering and architectural design, and building
code compliance have traditionally dealt either with advance specifications for a building which is
to be constructed, or with the forensic examination of a building or component after it has failed.
The science and practice of in-se vice building inspections and building conditions provide
an important but different base of experience about the way in which
buildings and building components fail, the causes of building failures, and the detection of
clues indicating that failures are developing.
In-service building inspections provide an opportunity to detect
evidence of developing construction failures which (usually) have not yet reached such dire conditions as to
be obvious to the lay person.
The home inspection profession (contrasted with the "home inspection industry")
focuses on in-service field conditions and as such has developed its own unique education, standards, ethics,
and practices. Yet it also requires an understanding
of design, codes, and building standards as well as traditional failure analysis.
Frequently Asked Questions (FAQs) about how to diagnose & repair structural foundation damage or movement or cracks
Question: after a foundation company installed a foundation the back door won't shut correctly and the concrete blocks are cracking all around the house
My mother decided after 3 yrs it was wise to install block foundation. A company installed her foundation with block. then she noticed her back door was shutting correctly and the block all around the house was cracked.
She called this company back and he proceeded to fix it saying his concrete was probably bad and reported it to his insurance. After a couple of weeks after he so called fix it the home has bad cracks again and the door never fixed correctly. I feel there taking advantage of my mothers no knowledge.
Can you help with advise or what is the correct procedure thx.
I apologize correction: kitchen door was NOT shutting correctly..
- Elsa Lopez
Reply:
Elsa, take a look at the types of foundation cracking, causes, repairs, beginning at FOUNDATION CRACKS & DAMAGE GUIDE. With so little information I cannot guess accurately about what went wrong. We'd need a lot of information about what was already there, what problem was being solved, and what work was done.
In other words, before we can begin even thinking about a foundation repair (other than perhaps emergency support in dire cases), we need to know
- the extent of building movement and damage
- the effects of those events on the structure
- the cause(s) of the movement
But in any case I agree that foundation cracking all around a house sounds like a serious mistake that needs to be diagnosed accurately before any further amateur repair work is undertaken.
You might find a foundation expert in our EXPERTS DIRECTORY or among local foundation repair companies or from an engineering firm PROVIDED the engineer actually has personal experience with residential building foundation inspection, diagnsosis, and repair.
Keep us posted.
Questions & Answers regarding this article
Questions & answers on how to evaluate, diagnose, & repair foundation cracks, leans, bulges, movement, damage
Critique, contributions wanted: Contact Us to suggest corrections or additions to articles at this website, and if you wish, to receive online listing and credit as a contributor. Particular thanks are due to the many experts and also consumers who read and critique technical articles at InspectAPedia.com.
Additional technical contributors & reference sources for this article are listed below.
Use links just below or at the left of each page to navigate this document or to view other topics at this website. Green links show where you are in our document or website.
"Concrete Slab Finishes and the Use of the F-number System", Matthew Stuart, P.E., S.E., F.ASCE, online course at www.pdhonline.org/courses/s130/s130.htm
Sal Alfano - Editor, Journal of Light Construction*
Thanks to Alan Carson, Carson Dunlop, Associates, Toronto, for technical critique and some of the foundation inspection photographs cited in these articles
Arlene Puentes, ASHI, October Home Inspections - (845) 216-7833 - Kingston NY
Greg Robi, Magnum Piering - 800-822-7437 - National*
Dave Rathbun, P.E. - Geotech Engineering - 904-622-2424 FL*
Ed Seaquist, P.E., SIE Assoc. - 301-269-1450 - National
Dave Wickersheimer, P.E. R.A. - IL, professor, school of structures division, UIUC - University of Illinois at Urbana-Champaign School of Architecture. Professor Wickersheimer specializes in structural failure investigation and repair for wood and masonry construction. *
Superior Walls of America, Ltd, 937 East Earl Road, New Holland, PA 17557, Phone: 1-800-452-9255, Fax: 717-351-9263. Website: http://www.superiorwalls.com/ Technical support:
Ed Helderman our Codes and Standards Manager. Email: ehelderman@superiorwalls.com or 717-351-9744
Robert Hare, Director of Technical Operations, rhare@superiorwalls.com, Tel: 717.351.9735
Thanks to Robert Hare for technical critique & content suggestions for this article - August 2010
Superior Walls of America Builder Guideline Booklet MAN 42-9000 booklet, [local copy] web-search 09/01/2010 original source (indirect link): http://www.superiorwalls.com/faq.php?&answers=1&details=53
FOUNDATION DAMAGE SEVERITY - How to Evaluate the Significance or Amount of Foundation Movement when a foundation is leaning, bulging, bowing, or settling
See FOUNDATION DAMAGE SEVERITY for our discussion of how to evaluate and report the severity of building foundation damage. A few examples are provided just below.
Historical data is a key observation or data that needs to be collected to assess the significance of any evidence of foundation movement
New or sudden foundation movement: If foundation cracking or movement is new, recent, or sudden: serious, prompt action is needed and you should consult an expert, in particular
if the amount is more than trivial. Trivial movement would be the discovery of a hairline crack (less than 1/16" in width) or a shrinkage crack
in a building foundation wall or floor slab. A word of caution: sometimes a crack has been present for a long time at a building but has simply
not been noticed by the building owner or occupants. The first time such a crack is seen it may be mistaken for "new" and "sudden" when that is
not the case. See our discussion of SHRINKAGE vs EXPANSION vs SETTLEMENT.
Recurrent foundation cracking or movement: action is probably needed since recurrent movement can lead to cumulative damage to some structures
even if the amount of movement is not great. In particular, if you have made cosmetic repairs to a foundation or to plaster or drywall finished
areas above and supported by such a foundation you may see that the cracks you repaired have simply recurred.
Long term, continuing, but slow foundation movement: action may be needed, particularly if the effects of long term foundation
movement are cumulative.
Initial foundation cracking or other limited damage occurring at time of construction such as foundation
cracks in a masonry block wall which occurred during backfill may not need other than cosmetic repairs, in particular if there is no
evidence of subsequent foundation movement and still more likely if the initial damage and amount of movement was minor (say less than 1/2"
of inwards foundation wall bulge in the cracked areas.)
Foundation damage due to being struck: in this case the foundation will certainly need repair if the damage
to it was extensive with collapsed or severely dislocated components. Trivial foundation damage, say cracking a masonry block
on the corner of a garage with no basement below, is less likely to be significant.
Initial foundation settlement may not require additional repair. A hairline to 1/16" vertical crack in a concrete wall or
similar dimension step cracking in a masonry block wall may need cosmetic and sealant repair (to reduce leakage through the wall,
but if the initial amount of settlement was very small and is not ongoing, repair is unlikely to be needed.
These examples of foundation damage are almost always very important and need expert attention
Dislocated gas, plumbing, or electrical wiring or piping: NOTE: ANY foundation damage or crack associated with significant displacement of original structural or mechanical (gas/sewer lines) components is
likely to be significant. Even slight displacement is significant if mechanical systems may be unsafe (earthquake). Dislocated gas lines means
gas leaks are likely and there is serious damage of catastrophic explosion. Vacate the property, and immediately call the gas company from a telephone that is
not exposed to gas fumes.
Dislocated or broken structural connections such as a building which has shifted off of its foundation or has broken sill bolts or straps
connecting the foundation to the building framing needs expert investigation and repair.
Bulging foundation walls in response to area flooding are at risk of collapse; temporary support of the building and other measures
to relieve stress on the foundation may be needed. Do not delay in seeking expert advice in this situation.
This list is not complete. Suggestions welcomed.
Foundation Inspection Standards - ASHI Standards of Practice (American Society of Home Inspectors)
Daniel Friedman - ASHI Member (1986-2006) - building failures researcher.
"Concrete Slab Finishes and the Use of the F-number System", Matthew Stuart, P.E., S.E., F.ASCE, online course at www.pdhonline.org/courses/s130/s130.htm
Sal Alfano - Editor, Journal of Light Construction*
Thanks to Alan Carson, Carson Dunlop, Associates, Toronto, for technical critique and some of the foundation inspection photographs cited in these articles
Arlene Puentes, 845-339-7984, is an ASHI member and a licensed home inspector in Kingston, NY, and has served on ASHI national committees as well as HVASHI Chapter President. Ms. Puentes can be contacted at ap@octoberhome.com.
Greg Robi, Magnum Piering - 800-822-7437 - National*
Dave Rathbun, P.E. - Geotech Engineering - 904-622-2424 FL*
Ed Seaquist, P.E., SIE Assoc. - 301-269-1450 - National
Dave Wickersheimer, P.E. R.A. - IL, professor, school of structures division, UIUC - University of Illinois at Urbana-Champaign School of Architecture. Professor Wickersheimer specializes in structural failure investigation and repair for wood and masonry construction. * Mr. Wickersheimer's engineering consulting service can be contacted at HDC Wickersheimer Engineering Services. (3/2010)
*These reviewers have not returned comment 6/95
Technical Edits, Changes, Amendments to This Document
09/01/2010 technical edits
09/23/2008 adding crawl space safety warnings and crawl space dyrout procedures
06/09/2010 adding flood damage to foundations - a flood damage investigation case suggests pre-existing cracks
08/03/2007 adding text, illustrations, content, organization changes, citations to authority
06/07/2007 adding text, illustrations, content
5/30/2007 editing to add content on foundation crack repair
9/23/2006 editing to clarify text and add content; Technical review (partial) by Arlene Puentes.
4/17/2006 editing to clarify text in several sections.
Books & Articles on Building & Environmental Inspection, Testing, Diagnosis, & Repair
Our recommended books about building & mechanical systems design, inspection, problem diagnosis, and repair, and about indoor environment and IAQ testing, diagnosis, and cleanup are at the InspectAPedia Bookstore. Also see our Book Reviews - InspectAPedia.
The Home Reference Book - the Encyclopedia of Homes, Carson Dunlop & Associates, Toronto, Ontario, 2010, $69.00 U.S., is available from Carson Dunlop. The Home Reference Book is a bound volume of more than 450 illustrated pages that assist home inspectors and home owners in the inspection and detection of problems on buildings. The text is intended as a reference guide to help building owners operate and maintain their home effectively. InspectAPedia.com ® editor Daniel Friedman is a contributing author. Field inspection worksheets are included at the back of the volume.
Design of Wood Structures - ASD, Donald E. Breyer, Kenneth Fridley, Kelly Cobeen, David Pollock, McGraw Hill, 2003, ISBN-10: 0071379320, ISBN-13: 978-0071379328
This book is an update of a long-established text dating from at least 1988 (DJF); Quoting: This book is gives a good grasp of seismic design for wood structures. Many of the examples especially near the end are good practice for the California PE Special Seismic Exam design questions. It gives a good grasp of how seismic forces move through a building and how to calculate those forces at various locations.THE CLASSIC TEXT ON WOOD DESIGN UPDATED TO INCLUDE THE LATEST CODES AND DATA. Reflects the most recent provisions of the 2003 International Building Code and 2001 National Design Specification for Wood Construction. Continuing the sterling standard set by earlier editions, this indispensable reference clearly explains the best wood design techniques for the safe handling of gravity and lateral loads. Carefully revised and updated to include the new 2003 International Building Code, ASCE 7-02 Minimum Design Loads for Buildings and Other Structures, the 2001 National Design Specification for Wood Construction, and the most recent Allowable Stress Design.
Diagnosing & Repairing House Structure Problems, Edgar O. Seaquist, McGraw Hill, 1980 ISBN 0-07-056013-7 (obsolete, incomplete, missing most diagnosis steps, but very good reading; out of print but used copies are available at Amazon.com, and reprints are available from some inspection tool suppliers). Ed Seaquist was among the first speakers invited to a series of educational conferences organized by D Friedman for ASHI, the American Society of Home Inspectors, where the topic of inspecting the in-service condition of building structures was first addressed.
Defects and Deterioration in Buildings: A Practical Guide to the Science and Technology of Material Failure, Barry Richardson, Spon Press; 2d Ed (2001), ISBN-10: 041925210X, ISBN-13: 978-0419252108. Quoting: A professional reference designed to assist surveyors, engineers, architects and contractors in diagnosing existing problems and avoiding them in new buildings. Fully revised and updated, this edition, in new clearer format, covers developments in building defects, and problems such as sick building syndrome. Well liked for its mixture of theory and practice the new edition will complement Hinks and Cook's student textbook on defects at the practitioner level.
"Avoiding Foundation Failures," Robert Marshall, Journal of Light Construction, July, 1996 (Highly recommend this article-DF)
"A Foundation for Unstable Soils," Harris Hyman, P.E., Journal of Light Construction, May 1995
"Backfilling Basics," Buck Bartley, Journal of Light Construction, October 1994
"Inspecting Block Foundations," Donald V. Cohen, P.E., ASHI Reporter, December 1998. This article in turn cites the Fine Homebuilding article noted below.
"When Block Foundations go Bad," Fine Homebuilding, June/July 1998
Masonry structures: The Masonry House, Home Inspection of a Masonry Building & Systems, Stephen Showalter (director, actor), DVD, Quoting: Movie Guide Experienced home inspectors and new home inspectors alike are sure to learn invaluable tips in this release designed to take viewers step-by-step through the home inspection process. In addition to being the former president of the National Association of Home Inspectors (NAHI), a longstanding member of the NAHI, the American Society of Home Inspectors (ASHI), and the Environmental Standard Organization (IESO), host Stephen Showalter has performed over 8000 building inspections - including environmental assessments. Now, the founder of a national home inspection school and inspection training curriculum shares his extensive experience in the inspection industry with everyday viewers looking to learn more about the process of evaluating homes. Topics covered in this release include: evaluation of masonry walls; detection of spalling from rebar failure; inspection of air conditioning systems; grounds and landscaping; electric systems and panel; plumbing supply and distribution; plumbing fixtures; electric furnaces; appliances; evaluation of electric water heaters; and safety techniques. Jason Buchanan --Jason Buchanan, All Movie Review
Masonry Structures: Behavior and Design, Robert G. Drysdale, Ahmid A. Hamid, Lawrie R. Baker, The Masonry Society; 2nd edition (1999), ISBN-10: 1929081014, ISBN-13: 978-1929081011
Straw Bale Home Design, U.S. Department of Energy provides information on strawbale home construction - original source at http://www.energysavers.gov/your_home/designing_remodeling/index.cfm/mytopic=10350
More Straw Bale Building: A Complete Guide to Designing and Building with Straw (Mother Earth News Wiser Living Series), Chris Magwood, Peter Mack, New Society Publishers (February 1, 2005), ISBN-10: 0865715181 ISBN-13: 978-0865715189 - Quoting: Straw bale houses are easy to build, affordable, super energy efficient, environmentally friendly, attractive, and can be designed to match the builder’s personal space needs, esthetics and budget. Despite mushrooming interest in the technique, however, most straw bale books focus on “selling” the dream of straw bale building, but don’t adequately address the most critical issues faced by bale house builders. Moreover, since many developments in this field are recent, few books are completely up to date with the latest techniques. More Straw Bale Building is designed to fill this gap. A completely rewritten edition of the 20,000-copy best--selling original, it leads the potential builder through the entire process of building a bale structure, tackling all the practical issues: finding and choosing bales; developing sound building plans; roofing; electrical, plumbing, and heating systems; building code compliance; and special concerns for builders in northern climates.
Sinkholes and Sudden Land Subsidence References, Products, Consultants
"A Hole in the Ground Erupts, to Estonia's Delight", New York Times, 9 December 2008 p. 10.
History of water usage in Estonia: (5.7 MB PDF) jaagupi.parnu.ee/freshwater/doc/the_history_of_water_usage_systems_in_estonia.pdf
"Quebec Family Dies as Home Vanishes Into Crater, in Reminder of Hidden Menace", Ian Austen, New York Times, 13 May 2010 p. A8. See http://www.nytimes.com/
"Quick Clay", Wikipedia search 5/13/2010 - http://en.wikipedia.org/wiki/Quick_clay
Florida DEP - Department of Environmental Protection, & Florida Geological survey (http://www.dep.state.fl.us/geology/default.htm) on Florida sinkholes: Effects of Sinkholes on Water Conditions Hernando County, Florida, Brett Buff, GIS in Water Resources, 2008, Dr. David R. Maidment, Photos - Tom Scott, Florida Geographic Survey - Web Search 06/09/2010 - http://www.dep.state.fl.us/geology/geologictopics/jacksonsink.htm
and - http://www.dep.state.fl.us/geology/geologictopics/sinkhole.htm
also see
Lane, Ed, 1986, Karst in Florida: Florida Geological Survey Special Publication 29, 100 p.
Foundation Engineering Problems and Hazards in Karst Terranes, James P. Reger, Maryland Geological Survey, web search 06/05/2010, original source: http://www.mgs.md.gov/esic/fs/fs11.html Maryland Geological Survey, 2300 St. Paul Street, Baltimore, MD 21218
"Frost Heaving Forces in Leda Clay", Penner, E., Division of Building Research, National Research Council of Canada, Canadian Geotechnical Journal, NRC Research Press, 1970-2, Vol 7, No 1, PP 8-16, National Research Council of Canada, Accession number 1970-023601, Quoting from original source
The frost heaving forces developed under a 1 ft. (30.5 cm) diameter steel plate were measured in the field throughout one winter. The steel plate was fixed at the ground surface with a rock-anchored reaction frame. heave gauges and thermocouples were installed at various depths to determine the position and temperature of the active heaving zone. The general trend was for the surface force to increase as the winter progressed. when the frost line approached the maximum depth the force was in excess of 30,000 lb (13,608 KG). Estimates of the heaving pressure at the frost line ranged from 7 to 12 psi (0.49 to 0.84 KG/cm) square during this period. The variation of surface heaving force was closely associated with weather conditions. Warming trends resulting in a temperature increase of the frozen layer caused the forces to decline.
"Geoscape Ottowa-Gatineau Landslides", Canada Department of Natural Resources, original source http://geoscape.nrcan.gc.ca/ottawa/landslides_e.php - quoting from that source:
Leda clay slopes in the Ottawa valley are vulnerable to catastrophic landslides. More than 250 landslides, historical and ancient, large and small, have been identified within 60 km of Ottawa. Some of these landslides caused deaths, injuries, and property damage, and their impact extended far beyond the site of the original failure. In spectacular flowslides, the sediment underlying large areas of flat land adjacent to unstable slopes liquefies. The debris may flow up to several kilometres, damming rivers and causing flooding, siltation, and water-quality problems or damaging infrastructure. Geologists and geotechnical engineers can identify potential landslide areas, and appropriate land-use zoning and protective engineering works can reduce the risk to property and people.
Deposits of Leda clay, a potentially unstable material, underlie extensive areas of the Ottawa-Gatineau region. Leda clay is composed of clay- and silt-sized particles of bedrock that were finely ground by glaciers and washed into the Champlain Sea. As the particles settled through the salty water, they were attracted to one another and formed loose clusters that fell to the seafloor. The resulting sediment had a loose but strong framework that was capable of retaining a large amount of water. Following the retreat of the sea, the salts that originally contributed to the bonding of the particles were slowly removed (leached) by fresh water filtering through the ground. If sufficiently disturbed, the leached Leda clay, a weak but water-rich sediment, may liquefy and become a 'quick clay'. Trigger disturbances include river erosion, increases in pore-water pressure (especially during periods of high rainfall or rapid snowmelt), earthquakes, and human activities such as excavation
and construction.
After an initial failure removes the stiffer, weathered crust, the sensitive clay liquefies and collapses, flowing away from the scar. Failures continue in a domino-like fashion, rapidly eating back into the flat land lying behind the failed slope. The flowing mud may raft intact pieces of the stiffer surface material for great distances.
Kochanov, W. E., 1999, Sinkholes in Pennsylvania: Pennsylvania
Geological Survey, 4th ser., Educational Series 11,
33 p., 3rd printing April 2005, Pennsylvania Department of Conservation and Natural Resources / Bureau of Topographic and Geologic Survey, DCNR Educational Series 11, Pennsylvania Geological Survey, Fourth Series, Harrisburg,
1999 - web search 06/05/2010, original source: http://www.dcnr.state.pa.us/topogeo/hazards/es11.pdf - Quoting from the document introduction: The first 18 pages of this booklet contain an explanation of how sinkholes
develop. In order to tell the sinkhole story, it is important to discuss
a number of related geologic disciplines. The words used to describe sinkholes
and these disciplines may be a bit unfamiliar. However, general explanations
are given throughout the booklet to help clarify their meanings.
Key words are printed in bold type for emphasis. The more important
ones are defined in a Glossary that begins on page 29.
The remaining sections, starting with “Sinkholes in the Urban Environment”
(page 18), deal with sinkholes and their impact on our environment.
This includes recognition of subsidence features and sinkhole repair.
[1] Sarah Cervone, [web page] data from the APIRS database, Graphics by Ann Murray, Sara Reinhart and Vic Ramey, Vic Ramey is
the editor. DEP review by Jeff Schardt and Judy Ludlow. The web page is a
collaboration of the Center for Aquatic and Invasive Plants, University of Florida, and the Bureau of Invasive
Plant Management, Florida Department of Environmental Protection contact: varamey@nersp.nerdc.ufl.edu [A primary resource for this article
[2] Center for Cave and Karst Studies or the
Kentucky
Climate
Center, both at
Western
Kentucky
University
Vanity Fair - web search 06/04/2010 http://www.vanityfair.com/online/daily/2010/06/what-caused-the-guatemala-sinkhole-and-why-is-it-so-round.html
Sinkholes, Virginia Division of Mineral Resources,
Virginia Department of Mines, Minerals and Energy, www.dmme.virginia.gov Virginia Department of Mines, Minerals and Energy
Division of Mineral Resources
900 Natural Resources Drive, Suite 500
Charlottesville, VA 22903
Sales Office: (434) 951-6341 FAX : (434) 951-6365
Geologic Information: (434) 951-6342
http://www.dmme.virginia.gov/
divisionmineralresources.shtml - Web search 06/09/2010
Sink Hole & Related Engineering References
Newton, J. G., 1987, Development of sinkholes resulting from man's activities in the eastern United States: US Geological Survey Circular 968, 54 p.
Sinclair, W. C., 1982, Sinkhole development resulting from ground-water withdrawal in the Tampa Area, Florida: U.S. Geological Survey Water-Resources Investigations 81-50, 19 p.
White, W. B., 1988, Geomorphology and Hydrology of Karst Terrains: Oxford University Press, New York, 464 p.
Williams, J. H. and Vineyard, J. D., 1976, Geologic indicators of subsidence and collapse in karst terrain in Missouri: Presentation at the 55th Annual Meeting, Transportation Research Board, Washington, D.C.
Barry F. Beck, A. J. (1999). Hydrogeology and Engineering Geology of Sinkholes and Karst. Rotterdam, Netherlands: A. A. Balkema.
Beck, B. F. (2003). Sinkholes and the Engineering and Environmental Impacts of Karst. Huntsville, Alabama: The American Society of Civil Engineers.
Beck, B. F. (2005). Sinkholes and the Engineering and Envrionmental Impacts of Karst. San Antonio, Texas: The American Society of Civil Engineers.
Tony Waltham, F. B. (2005). Sinkholes and Subsidence, Karst and Cavernous Rocks in Engineering and Construction. Chichester, United Kingdom: Praxis Publishing.
Whitman D., G. T. (1999). Spatial Interrelationships Between Lake Elevations, Water Tables, and Sinkhole Occurence in Central Florida: A GIS Approach. Photogrammetric Engineering and Remote Sensing , 1169-1178.
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