Coastal & Marine Geology InfoBank

Home FACS Activities Atlas Geology School Related Sites More

USGS CMG InfoBank: Stress and Strain

Skip navigational links
Dictionaries: Our Mapping Systems   The USGS and Science Education   USGS Fact Sheets   Topics   Keywords   Data Dictionary   Metadata Dictionary   Computer Terminology   Digital Formats  
InfoBank Terms: Activity ID   activity overview   crew   digital data   formal metadata   lines   metadata   NGDC   port stops   project/theme   region   ship   stations   time   virtual globe   year  
Data Types: bathymetry   biological   geochemical   gravity   ground penetrating radar   imaging   LIDAR   logs   magnetics   metering equipment   navigation   samples   seismic   total station   definitions disclaimer  
Data Formats: ARC coverage   E00   FGDC metadata   gridded/image   imaging   material   scattered/swath   Shapefile   vector/polygon  
Comment: 13:44 - 14:46 (01:02)
Source: Annenberg/CPB Resources - Earth Revealed - 8. Earth's Structures
Keywords: "tectonic activity", fold, structure, "Dee Trent", compression, tension, stress, strain, "elastic strain", "elastic limit", earthquake, deformation

Our transcription: Geologic structures like folds and folds are examples of strain, a change in the shape of the rock caused by stress.
"Stress" is the application of force on an area.
If you lean against a wall, you're putting some stress on it.
A strain is when the wall moves, so "strain" is the change in shape or volume.
"Plastic strain" is where stress has been applied to an object, and it's deformed, and then it stays in that same shape -- it doesn't resume its original shape.
"Elastic strain" is where the object is deformed, and then when the stress is removed it returns to its original shape.
Now, if you exceed its "elastic limit", then the object will break and shatter.
That's when we see folded rocks.
They have been subjected to a plastic strain.
Fracturing occurs when the strain exceeds the elastic limits of a material, and the rock breaks or fractures.

Geology School Keywords
Skip footer navigational links

Coastal and Marine Science Centers:  Pacific   St. Petersburg   Woods Hole  
InfoBank   Coastal and Marine Geology Program   Geologic Information   Ask-A-Geologist   USGS Disclaimer  

Accessibility FOIA Privacy Policies and Notices

Take Pride in America logo logo U.S. Department of the Interior | U.S. Geological Survey
Page Contact Information: InfoBank staff
Page Last Modified: Thu Oct 31 04:28:23 PDT 2013  (chd)