GROUND SUBSIDENCE AND KARST SUBSIDENCE Flashcards
Defined as the lowering of the land surface due to
sinkhole development
Surface Subsidence and Collapse
True or False: Sudden collapse events are major disasters.
False
Water in the atmosphere can dissolve small amounts
of carbon dioxide (CO2). This results in rain water having a small amount of carbonic acid (H2CO3) when it falls on the Earth’s surface.
Carbonate Dissolution
Mining activities that ______________________ can result in collapse if precautions are not taken to ensure that the there is adequate
support for the overlying rocks.
remove material from below the surface
If fluids are withdrawn from below the surface, a decrease in fluid pressure may occur resulting in the removal of support and possible collapse.
Subsidence Caused by Fluid Withdrawal
The two most important fluids that occur beneath
the surface are
water (in the form of groundwater)
and petroleum (in the form of oil and natural gas).
In the Wilmington oil field of Long Beach, California, subsidence was first recognized in 1940 and has costed the United States government over ___________. Near the center of this area, the surface subsided by up to ______________.
$100 million, 9 meters
The word derives from the Slovene word dolina, meaning a
depression in the landscape.
Doline
Give two processes that can form dolines.
- surface solution
- cave collapse
- piping
- subsidence
- stream removal of superficial covers
Five-fold classification of dolines
- Solution Dolines
- Collapse Dolines
- Suffossion Dolines
- Subsidence Dolines
- Alluvial stream-sink dolines
start where solution is concentrated around a favorable point such as joint intersections. The solution lowers the bedrock surface, so eating out a small depression. The depression traps water, encouraging more solution and depression enlargement.
A. Solution Dolines
B. Collapse Dolines
C. Suffossion Dolines
D. Subsidence Dolines
E. Alluvial stream-sink dolines
A. Solution Dolines
form in an analogous manner to subjacent karst-collapse dolines,
with a blanket of superficial deposits or thick soil being washed or falling into widened joints and solution pipes in the limestone beneath.
A. Solution Dolines
B. Collapse Dolines
C. Suffossion Dolines
D. Subsidence Dolines
E. Alluvial stream-sink dolines
C. Suffossion Dolines
are produced suddenly when the roof of a cave formed by
underground solution gives way and fractures or ruptures rock and soil.
A. Solution Dolines
B. Collapse Dolines
C. Suffossion Dolines
D. Subsidence Dolines
E. Alluvial stream-sink dolines
B. Collapse Dolines
form in alluvium where streams descend into underlying calcareous rocks. The stream-sink is the point at which a stream
disappears underground.
A. Solution Dolines
B. Collapse Dolines
C. Suffossion Dolines
D. Subsidence Dolines
E. Alluvial stream-sink dolines
E. Alluvial stream-sink dolines
form gradually by the sagging or settling of the ground
surface without any manifest breakage of soil or rock
A. Solution Dolines
B. Collapse Dolines
C. Suffossion Dolines
D. Subsidence Dolines
E. Alluvial stream-sink dolines
D. Subsidence Dolines
