A sag pond is a body of fresh water[ THE SAG POND STORY – INTERPRETIVE TRAIL GUIDE, retrieved May, 9th 2017] collected in the lowest parts of a depression formed between two sides of an active geologic fault zone.[ Nevada-Government Dictionary on Water Words, retrieved April, 3rd 2012][geology.gsapubs.org/content/37/11/967.abstract Simpson, E.L., et al. "An upper cretaceous sag pond deposit: Implications for recognition of local seismicity and surface rupture along the Kaibab monocline, Utah." Geology. Web. Accessed May 9th, 2017.]
Formation
A sag pond is formed along a strike-slip fault, which may create a
topography.
[[3] Alden, Andrew. "Tectonic Landforms." ThoughtCo. Web. Accessed May 9th, 2017.][ THE SAG POND STORY – INTERPRETIVE TRAIL GUIDE, retrieved May, 9th 2017] When water enters the depression from rivers, streams, rainfall or snowfall, it fills the low-lying area, and a pond is the result.
[[5] Keiffer, Robert J. 2011. "Ancient sag ponds add to diversity at HREC." Web. Accessed May 9th, 2017.]
Scientific significance
Sag pond formation is common in
California,
[[6] Keiffer, Robert J. 2011. "Ancient sag ponds add to diversity at HREC." Web. Accessed May 9th, 2017.] and many of them can be found on the San Andreas Fault, which runs through the western part of the state.
[[7] Alden, Andrew. "Tectonic Landforms." ThoughtCo. Web. Accessed May 9th, 2017.][pangea.stanford.edu/~hilley/REPRINTS/Delongetal_Tectonics2010.pdf DeLong, Stephen B., George E. Hilley, Michael J. Rymer and Carol Prentice. "Fault zone structure from topography: Signatures of en echelon fault slip at Mustang Ridge on the San Andreas Fault, Monterey County, California." 2010. Tectonics, Vol. 29. Web. Accessed May 9th, 2017.] Aerial photography or high-resolution
topography can easily determine their locations.
[pangea.stanford.edu/~hilley/REPRINTS/Delongetal_Tectonics2010.pdf DeLong, Stephen B., George E. Hilley, Michael J. Rymer and Carol Prentice. "Fault zone structure from topography: Signatures of en echelon fault slip at Mustang Ridge on the San Andreas Fault, Monterey County, California." 2010. Tectonics, Vol. 29. Web. Accessed May 9th, 2017.]
Uses
Sag ponds have been converted into stock reservoirs.
[ THE SAG POND STORY – INTERPRETIVE TRAIL GUIDE, retrieved May, 9th 2017] Larger sag ponds are converted into reservoirs for public water sources, such as San Andreas Lake
[[9] MobileRanger. Web. Accessed May 9th, 2017.]
Examples
Sag ponds of various sizes can be found along the San Andreas Fault, most notably within the
Carrizo Plain and Sierra Pelona Mountains. Some have been converted into reservoirs like the San Andreas Reservoir near San Bruno, California. Various lagoons on the
Achada Plateau of
Pico Island in the
Azores are the result of a
graben.
Sources
