Advertisement

You are browsing the archive for landslides Archives - AGU Blogosphere.

22 June 2021

Low-displacement landslides explain unusual West Virginia landscape features visible in lidar imagery

Like so many older landslides in the Appalachians, the significance and cause of these features is unknown. Because they are so numerous and are only visible using lidar data acquired in 2016, they may represent an untapped resource of useful information about the recent history of Appalachian landscapes.

Read More >>


24 March 2021

What does that landslide actually look like, part 2: an active landslide

As indicated in the previous post, lidar-derived imagery still needs ground-truthing to maximize its usefulness as a means of characterizing landslides and other slope failures. Last June, Ken Gillon and I visited the Rutherford County, North Carolina, landslide described below as part of our work with Appalachian Landslide Consultants, PLLC (ALC) on behalf of the North Carolina Geological Survey. This slide caught my eye in lidar hillshade imagery because it appeared to share characteristics with an active slide we had visited a few days before.

Read More >>


1 March 2021

What does that landslide actually look like?

We have no constraints on the age of the slides, but they may reflect logging history in the area. The majority of these slopes were heavily and continuously logged during the past ~150 years, with logging in this area clearly occurring within the past 50 years. The slides may have developed after clear-cuts, with the rapid return of vegetation common in the region quickly making the area look less disturbed than it really is.

Read More >>


24 February 2021

Lidar-derived imagery of 1949 debris flows on North Fork Mountain, Grant County, West Virginia

Debris flow events present a significant hazard to life and property in all parts of the Appalachians. The 1949 event that created the features shown here caused 8 fatalities and displaced a tremendous number of residents. Detailed mapping…along with analysis of detailed surface imagery, can greatly enhance understanding of where debris flows begin and where they travel. This understanding, in turn, can potentially reduce the human impact of these particularly dynamic and mobile slope failure events.

Read More >>


4 December 2020

Lidar hillshade imagery hints at the location of a future coal spoil landslide

A coal spoil landslide in southeastern Wise County, Virginia, appears traceable to a faint scarp visible in the spoil pile in a 2017 lidar dataset. The slide pre-dates October 2019 Google Earth imagery and post-dates the 2017 lidar data acquisition.

Read More >>


5 October 2020

Interesting “sideways” movement of a large sandstone blockslide

A large sandstone blockslide in Highland County, Virginia presents an unusual appearance in LiDAR hillshade imagery–it appears to have moved sideways across a slope instead of directly down the slope.

Read More >>


24 September 2020

LiDAR reveals the cloth-like appearance of a “wrinkled” translational landslide

The Virginia Valley and Ridge hosts plenty of amazing landslide features, but this wrinkled translational slide in Botetourt County, Virginia is particuarly eye-catching. It reminds me of the wrinkling that might occur in a thin layer of cloth pushed along a smooth surface–something like pushing a napkin or tablecloth along a tabletop.

Read More >>


28 August 2020

The Geo Models: Landslides associated with historic iron mining in the Virginia Valley and Ridge

The sharpness of these landslide features suggests they may still be slowly moving, but very little disruption to vegetation is visible in satellite imagery, so movement is probably very slow. Since their maximum age is known (the time of mining; late 1800s-1920s), they offer interesting comparison to older, natural landslides in the area, which tend to have softened, rounded features due to weathering and erosion.

Read More >>


21 July 2020

Is this Florida’s most famous landslide?

New from The Geo Models blog: “I asked Google and was rewarded with a vintage paper called…wait for it…’A Florida Landslide.’ Written in 1948 by Richard Jordan of Florida State, the paper describes a surprisingly impressive landslide that occurred in Gadsden County, Florida…”

Read More >>


22 May 2020

Slump landslide models, with some rock or debris avalanche characteristics

New from The Geo Models blog: “The model landslides in this post were produced at the same time as the Llusco landslide model I wrote about last year. They were created using a similar setup, but the slide masses behaved very differently during movement.”

Read More >>


11 February 2020

Climate change could trigger more landslides in High Mountain Asia

More frequent and intense rainfall events due to climate change could cause more landslides in the High Mountain Asia region of China, Tibet and Nepal, according to the first quantitative study of the link between precipitation and landslides in the region.

Read More >>


5 August 2019

Toreva Block landslide models

Somewhere on the AGU Landslide blog, I came across a reference to another type of rock strength-controlled, intact landslide I had never heard of–the Toreva Block. Like the Appalachian Valley and Ridge giant landslides, it is possible to replicate Toreva-style movement with contrasting model materials that represent failure-prone shale and much stronger topography-supporting lithologies, like sandstone or basalt.

Read More >>


20 June 2019

A sand model landslide compared to the 2018 Llusco event (with coordinates of the Llusco slide!)

If you Google the word “landslide”…the first search result you get is the Fleetwood Mac song. I suppose this says something about the place of Earth Science in the 2019 world, but whatever (more on this at the end of the post!). Clicking the “Images” tab improves things, assuming you are indeed seeking information about the geologic feature.

Read More >>


7 March 2019

The Breaks rock slide: Revisiting Schultz and Southworth (1989) 30 years later

By Philip S. Prince, Virginia Division of Geology and Mineral Resources (Scroll down for summary video link) The Breaks rock slide, a large slide feature at the western edge of the Appalachian fold-thrust belt, was first described 30 years ago in Schultz and Southworth (1989). In an impressive display of imagery analysis and general geologic know-how, the authors successfully identified several large but topographically subtle ancient landslide features without the …

Read More >>


7 January 2019

LiDAR-based hillshades show details of thin “slab-slides” in Appalachian Valley and Ridge

Hillshade imagery from a new LiDAR dataset provides an incredibly detailed look at landslides of unknown age within the Valley and Ridge province.

Read More >>


4 January 2019

The ten most important landslide events of 2018

2018 will be remembered as a year of extraordinary landslides. This is my list of the ten most important landslide events of 2018

Read More >>


21 December 2018

Landslide probability may depend more on riverside steepness than on hillsides above

On April 25, 2015, a 7.8-magnitude earthquake stuck the Gorkha region of Nepal near the capital city of Kathmandu. Approximately 9,000 people died and more than 22,000 suffered injuries. The quake also triggered more than 20,000 landslides in the surrounding area. A team of scientists at the University of Southern California is studying how the topography of the Melamchi Valley in Gorkha affected the incidence of landslides after the 2015 earthquake.

Read More >>


25 July 2018

A “duct tape and WD-40” approach to digital topography and geologic mapping

By Philip S. Prince Google Earth is amazing, but sometimes tree cover and land use obscure subtle but significant surface features critical to mapping and interpretation. Digital elevation and terrain models provide a way around this, but without ArcScene, SketchUp, or a similar program they lack the 3-D reality of Google Earth in oblique perspective. Addtionally, hillshade terrain models can produce an inversion effect for observers when seen in plan …

Read More >>


19 February 2018

Bringing down mountains: more landslides

…this time Phil has built a model comparing translational slides with rotational or slump landslides.

Read More >>


13 February 2018

Going with the Flow

A translational landslide is when rock or soil moves down-slope along a plane of weakness like a joint, fault or bedding surface. Best illustrated with chocolate and a weaker layer of caramel.

Read More >>