Types of Landslides

Rock Falls
Earth Slumps
Rock Spread
Rock Slumps
Complex
Birth & Development
Varnes Classification

Rock Falls are defined as free falling rocks from a steep cliff or slope, along an undercut stream bank or an eroding valley wall. They occur mainly in the Greenhorn Limestone of Cretaceous age and in the Permian and Pennsylvanian aged rocks in eastern Nebraska and in the Arikaree, and Ogallala groups of Tertiary age in western Nebraska. Seventeen rockfalls were recorded in this study.

Source: Landslide Inventory Along Nebraska State-Federal Roadway System (MP-39), Section 2.2, by Duane A. Eversoll, CSD Research Geologist, 1991.

Urban Rock Fall in Wildcat Hills area near Scottsbluff, Nebraska. Photo by Jack Shroeder, University of Nebraska-Omaha.

Rock Fall at Ponca State Park, Nebraska. The boat ramp to the Missouri River is on the left.

Earth Slumps are defined as non-bedrock deposits (loess, glacial materials, etc.) that move downward on a rotational failure plane. Of the 209 landslides inventoried, 108 were classified as earthslumps. Earthslumps are the most widespread and common type of landslide found in Nebraska. They develop mainly in loess and glacial deposits. One landslide was classified as a debris slump.

Source: Landslide Inventory Along Nebraska State-Federal Roadway System (MP-39, Section 2.4, by Duane A. Eversoll, CSD Research Geologist, 1991.

Urban Earth Slump in Omaha, Nebraska near 106th and Pacific Streets.

Knox County. A county road Earth Slump, north of Center, Nebraska.

Earth Slump, Fremont, Nebraska. A close-up of the homes on top of the landslide is in the next photograph.

Close-up from the previous photograph of the Earth Slump near Fremont, Nebraska. At least three houses were moved due to this threatening landslide. The slide was probably caused by individual septic systems and underground sprinkler systems saturating the bluff overlooking the Platte River. — Close-up from the image to the left of the Earth Slump near Fremont, Nebraska. At least three houses were moved due to this threatening landslide. The slide was probably caused by individual septic systems and underground sprinkler systems saturating the bluff overlooking the Platte River.

Rock Spreads are defined as blocks or slabs of bedrock that move laterally usually without a well-defined controlling basal shear surface or zone of plastic flow. Examples in Nebraska were observed along the south-central border and involved Cretaceous Greenhorn Limestone with lateral extension (movement) on the underlying Graneros Shale of Cretaceous age. Only one landslide was classified as a rockspread in this study.

Source: Landslide Inventory Along Nebraska State-Federal Roadway System (MP-39), Section 2.5, by Duane A. Eversoll, CSD Research Geologist, 1991.

Rock Spread in Hitchcock County, Nebraska. Note the blocks of Ogallala.

Rock Slumps are defined as a mass of bedrock that moves downward on a rotational failure plane. Seventy of the landslides inventoried for this study were classified as rockslumps. A majority of these rockslumps, occurred in the Pierre Shale of Cretaceous age.

Source: Landslide Inventory Along Nebraska State-Federal Roadway System (MP-39), Section 2.5, by Duane A. Eversoll, CSD Research Geologist, 1991.

Rock Slump in Pierre Shale on Highway 13, Knox County, Nebraska.

According to Varnes (1978) movement is by a combination of one or more of the principal types of landslides. Many landslides are complex, although one type of movement dominates over the other types in certain areas of a slide or at a particular time. Older and larger slides such as those observed along major river bluffs involving younger deposits overlying older bedrock were classified as complex. Thirteen landslides were classified as Complex.

Source: Landslide Inventory Along Nebraska State-Federal Roadway System (MP-39), Section 2.6, by Duane A. Eversoll, CSD Research Geologist, 1991.

Complex landslide on Highway 14, two miles South of Niobrara, Nebraska. See an enlargement of this photograph which includes details of this complex landslide. The next photograph is a close-up of the area in the yellow rectangle.

Highway 14, Knox County, Nebraska. Close-up of the area featured in the green rectangle. Same Complex landslide as the above two photographs, but two years later. The highway dropped over six feet just after it was re-routed through the hills on the left.

Overnight settlement on Complex landslide on Highway 14, two miles South of Niobrara, Nebraska. This photograph is a close-up of the area in the yellow rectangle from the previous photograph.

The Birth and Development of a Landslide Located Five Miles West of Lincoln on Interstate 80

Varnes Classification of Slope Movements, 1976

Type of Movement			Type of Material
			Bedrock	Engineering Soils
				Predominately coarse	Predominately fine
Falls			Rock fall	Debris fall	Earth fall
Topples			Rock topple	Debris topple	Earth Topple
Slides	Rotational Translational	few units many units	Rock slump	Debris slump	Earth slump
			Rock block slide	Debris block slide	Earth block slide
			Rock slide	Debris slide	Earth slide
Lateral Spreads			Rock spread	Debris spread	Earth spread
Flows			Rock flow (deep creep)	Debris flow (soil creep)	Earth flow
Complex		Combination of two or more principal types of movement