Geologic Structures (Part 4)
Strike-slip Faults
• If rock blocks slide past each other in a horizontal direction, the fault is called a strike-slip fault. Strike-slip faults are caused by lateral shear stress.
Strike-slip fault (Diagram by Phyllis Newbill)
Strike-slip fault in the field (Photograph by Stan Johnson)
The above photograph shows a strike-slip fault in Virginia.
Environmental Effects of Faulting
• Faults are important because, like joints, they create surfaces along which fluids (such as oil or water) can travel.
Groundwater along a fault (Photograph by Rober Whisonant)
Faults are important for groundwater storage and movement. The photograph above shows how groundwater has moved through rocks along a fault. Iron stains on the rock indicate that water has flowed out of this fault exposure. This picture was taken in Tazewell County.
• Faults can also provide potential surfaces along which rocks can slide.
• If faults move suddenly, they generate earthquakes.
Rock slide along a fault (Photograph by Robert Whisonant)
The photograph above shows a huge rock block sticking out of a road cut because the block has slid along a fault plane. This cut is near Bluefield.