Search results
Results From The WOW.Com Content Network
A rotational slump occurs when a slump block, composed of sediment or rock, slides along a concave-upward slip surface with rotation about an axis parallel to the slope. [3] Rotational movement causes the original surface of the block to become less steep, and the top of the slump is rotated backward.
Tilted block faulting, also called rotational block faulting, is a mode of structural evolution in extensional tectonic events, a result of tectonic plates stretching apart. [ 1 ] [ 2 ] When the upper lithospheric crust experiences extensional pressures, the brittle crust fractures, creating detachment faults . [ 3 ]
[1] Convective instabilities facilitate delamination. The convection can simply peel away the lower crust or, in a different scenario, a Rayleigh–Taylor instability is created. Due to the instability in a local area, the base of the lithosphere breaks up into descending blobs fed by an enlarging region of thinning lithosphere.
Mass wasting, also known as mass movement, [1] is a general term for the movement of rock or soil down slopes under the force of gravity. It differs from other processes of erosion in that the debris transported by mass wasting is not entrained in a moving medium, such as water, wind, or ice.
Rotational components of strong ground motions refer to variations of the natural slope of the ground surface due to the propagation of seismic waves. [1] Earthquakes induce three translational (two horizontal and one vertical) and three rotational (two rocking and one torsional ) motions on the ground surface.
It can also be significant in coastal areas when sea level falls after a storm tide, or when the water level of a reservoir or even a natural lake rapidly falls. The most famous example of this is the Vajont failure, when a rapid decline in lake level contributed to the occurrence of a landslide that killed over 2000 people. Numerous huge ...
Cracks can also form in the Sherack Formation, causing weakness in the underlying clay, and slumping. The exposed contact between the formations (commonly in the Red River area), and thus the inherent weakness at this contact, causes mass wasting of the river bank. [11] Human activity near the banks of the river then increases failure risks. [1]
The principle of original horizontality states that layers of sediment are originally deposited horizontally under the action of gravity. [1] It is a relative dating technique. The principle is important to the analysis of folded and tilted strata. It was first proposed by the Danish geological pioneer Nicholas Steno (1638–1686).