Humboldt State
University Department of Geology
Because of copyright restrictions, these slide and overhead
transparency files are password protected and limited to use by
students enrolled in Geology classes at Humboldt State University
Lecture Slides:
Landslides
Falls
Rockslides
- Rockslide
or block glide diagram -- slides fail along planar
surfaces
- Rockslide
-- along jointing parallel to slope, S. Fork Smith R. road,
CA
- Rockslide
-- along jointing dipping out of slope, Chuckanut Dr. near
Bellingham, WA
- Rockslide
-- Gros Ventre rockslide as seen from Jackson Hole, WY. Occurred
in 1925.
- Rockslide
-- Gros Ventre rockslide scar seen from across Gros Vente
R.
- Rockslide
-- toe of Gros Ventre rockslide: remnants of 250 ft high landslide
dam
- Huge
rockslide -- Blackhawk slide: huge prehistoric rockslide in
Mojave desert, CA. View up slide debris toward source.
- Huge
rockslide -- Blackhawk slide: huge prehistoric rockslide in
Mojave desert, CA. View down slide debris toward toe.
Debris Slides and Flows
- Debris
slide diagram -- debris fails on planar surface approximately
parallel to the slope; it may incorporate water and become a
debris flow
- Small
debris slide -- view of scar on slope below Hwy. 299 Berry
Summit overlook, Humboldt Co., CA. Occurred 1982.
- Small
debris slide -- view of debris flow deposits below Berry
Summit 1982 debis slide
- Runout
of debris flow deposits -- Berry Summit 1982 debris slide:
debris flowed nearly all the way down to old Hwy. 299
- Revegetation
of debris slide scar -- one year later, Berry Summit 1982 scar
is already being obscured
- Debris
slides in hillslope hollows -- panorama of head of Lone Tree
Cr, Mt. Tamalpais, Marin Co. CA. Taken 1970.
- Debris
slides in hillslope hollows -- new slide has occured in a
hollow, Lone Tree Cr., 1974. Compare with previous photo.
- Debris
slide in hillslope hollow -- overall view of 1974 Lone Tree
Cr. slide. Photo taken 1977.
- Head
of debris slide -- 1974 Lone Tree Cr. slide. Photo taken April
1974.
- Exit
of debris slide -- 1974 Lone Tree Cr. slide. Photo taken April
1974.
- Healing
debris slides -- revegetating debris slides over 20 yr old,
South Branch Lone Tree Cr.
- Healed
debris slides -- completely revegetated and partly filled
scars visible at low sun angles, Lone Tree Cr.
- Debris
slide in populated area -- 1982 debris slide above Brisbane,
CA. Slide originated in a hillslope hollow.
- Large
debris slide -- failure in sheared rock related to placement
of logging road, Little Jones Cr., CA
- Large
debris slide -- aerial view of Rattlesnake Slide, So. Fork
Smith R., CA
- Head
of large debris slide -- the Rattlesnake slide failed in these
highly broken and weathered rocks
- Exit
of large debris slide -- debris from the Rattlesnake slide
exited via this bedrock chute; note slide debris in
foreground
Slumps and Slump-Flows
- Slump
diagram -- slumps fail on curving surfaces. They are common in
cohesive materials like clays. Slumps typically show back-tilted
blocks.
- Small
coastal slump -- shows curving slide plane and back-tilted
block. Cliffs south of Big Lagoon, Humboldt Co., CA
- Slump
-- typical slump in clay-rich materials, Puente Hills, CA
- Slump
caused by roadcut -- Puente Hills, CA
- Slump
features -- aerial photo of large-scale slumping of hillslopes
underlain by clay shales, San Emigdio Hills, CA
- Slump
features -- another aerial photo of slumping of hillslopes
underlain by clay shales, San Emigdio Hills, CA
- Slumping
of riverbanks -- along Missouri R near Sioux City, Iowa. Note
the large scale and obvious back-tilted blocks.
- Large-scale
slumping -- slumping of mesa rim along Rio Grande R. near
Gallup New Mexico
- Slump
- flow -- slumping along fresh roadcut for Hwy 101 Redwood
National Park bypass, 1987. The slumped material incorporated much
water and became a debris flow.
- Crack
indicating incipient sliding -- fresh roadcut along Hwy 101
Redwood National Park bypass, 1987.
Earthflows and Slump-Earthflows
- Earthflow
diagram -- earthflows fail by slow flowage downslope, almost
like "soil glaciers" . They usually occur in clay-rich materials.
They produce a wrinkly, hummocky, lumpy topography.
- Small
earthflows -- along Hwy 101 near Squaw Rock north of
Cloverdale, CA
- Slump-earthflow
diagram -- failure occurs by slumping at the head, and the
disrupted material moves downslope as an earthflow.
- Large
slump-earthflow -- these large slump-earthflows are occurring
in clays exposed on the east flank of the Horseheaven Hills in
eastern Washington
- Earthflow
topography -- earthflow in Franciscan melange. View west from
Berry Summit, Hwy. 299, Humboldt Co., CA
- Earthflow
topography -- detail of slump-earthflow west of Berry Summit,
Hwy. 299, Humboldt Co., CA
- Earthflow
topography -- earthflow in Franciscan melange, west bank South
Fork Eel R. along Hwy 101 north of Redway, CA
- Earthflow
topography -- earthflows in Franciscan melange along Van Duzen
R west of Bridgeville, CA
- Earthflow
topography -- detail of flowage away from resistant blocks in
melange, Van Duzen R west of Bridgeville, CA
- Earthflow
topography -- debris flow in clay at toe of earthflow, Van
Duzen R west of Bridgeville, CA
- Earthflow
topography -- old earthflow topography and active earthflow S
of Fleener Cr., Humboldt Co., CA
Vegetation Indicators of
Landsliding
- Drunken
forest -- trees tilted both upslope and downslope due to
rotation of slump blocks
Landslide Deposits
(Colluvium)
[top of page] [sedimentary
environments]
Andre Lehre
Last updated: 3 March 2003
