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22 May 2023

Lidar highlights impressive landslide density on the southern Appalachian Blue Ridge Escarpment, western North Carolina

With a high quality (0.5-meter resolution) lidar dataset, it’s hard to examine much of the Blue Ridge Escarpment without seeing a few landslide features. Some slopes have more than others, however, and I think the McDowell County slope shown below probably has the greatest density of slides I have seen in the last 3 years of mapping. The most likely explanation is an extreme precipitation event. This area was heavily impacted in both 1916 and 1940 by extreme rainfall events, and the clustering of slides and their lack of damage to mid-20th century road grades would fit a connection to either of the storms nicely. These McDowell County slopes also resemble slopes in the headwaters of the Moorman’s River west of Charlottesville, Virginia, which experienced numerous slides due to an exceptional thunderstorm event in 1995.


29 April 2023

A sandbox model of China’s “other” Rainbow Mountains that fits in the palm of your hand

While these colorful landforms get most of the hype, China hosts another, arguably more impressive, zone of colorful, tilted sedimentary layer mountains–the Keping fold-and-thrust belt. Located at the northern edge of the Tarim Basin, the Keping showcases elongated ranges of pink, green, purple, and tan mountains that stretch for 10’s of kilometers and are readily seen from Google Earth. I made this sandbox model in a couple of hours to shrink and fast-forward the development of the Keping fold-thrust belt. The layer sequence was specifically chosen to match the stratigraphy seen on the Keping mountain ridges.


25 April 2023

The Blacks Beach landslide: Why did part of the beach rise as the cliffs slid down?

The January 20, 2023, landslide at Blacks Beach near La Jolla, California, dramatically uplifted a small portion of the beach during the slide’s movement. The beach uplift produced an understandable reaction from onlookers, and many of the early comments on YouTube videos of the slide focused on why the uplift occurred. In this case, the uplift is directly related to what is below the land surface–weak mudstone layers that provide a nice slide plane underneath the base of the slope and the beach. I made these models to illustrate this slope failure scenario, and Blacks Beach provides a nice opportunity to relate scaled models to a real-world slide that happened to be filmed.