39 Structural Geology (Posters)

Added due to amount of discipline abstracts submitted.

Wednesday, 11 March 2026
9:00 AM - 12:00 PM
RCC, Lower Level Hall

Friction Is Overrated: How Melting Rock Can Help Landslides Go the Extra Mile

Paper number: 39-3
Program: Technical Sessions
Time: 9:00 AM – 9:00 AM

Authors

Abstract

Large volume landslides often travel greater distances than a simple frictional-kinetic energy model suggests is possible, assuming typical rock friction (Byerlee, 1978). This increased travel distance indicates there must be a mechanism decreasing friction during emplacement. The Arequipa volcanic landslide in Peru (Legros et al., 2000), Langtang Himalaya landslide (Takagi, 2007), Köfels landslide (De Blasio & Medici, 2016), east Transverse Mountains slide (Kieth et al., 2025), and the Sevier and Markagunt gravity slides in Utah (Holliday et al., 2023; Rivera et al., 2025), are well-documented landslides of varying scales that generated frictional melt, or pseudotachylyte. Pseudotachylyte is rare amongst landslides and is typically observed within deep seismogenic faults under high normal stress states. Studies show that frictional melt during slip within these faults is capable of reducing the friction to near zero (Di Toro et al., 2006), through melt lubrication. The presence of pseudotachylyte within a number of large volume landslides is evidence that melt was generated between contacts, and may have played an important role in reducing the friction between slip surfaces during emplacement. While there are a low number of known landslides that contain pseudotachylyte, it is rarely preserved in the rock record and may be more widespread within landslides than currently recognized (Kirkpatrick & Rowe, 2013). However, the processes by which pseudotachylyte forms during the emplacement of large volume landslides remains poorly understood. 

 

To this end, we  developed a simple one-dimensional numerical model which simulates landslide kinematics and frictional heat generation and dissipation. Using the model, we evaluated the parameter space to consider the landslide conditions which are most likely to achieve the temperatures needed to form pseudotachylyte (~1600 ℃). Our model shows necessary melt temperature is achieved very early in the emplacement history for slides with a thickness of >100 meters. Once a melt is generated, heat generation along the slide plane becomes negligible and the simulated landslide travels with little frictional resistance until the melt solidifies. To test the model, we consider pseudotachylyte generated by the Sevier gravity slide. Using known parameters like slope, rock properties, and size we confirm that the slide can generate enough heat to melt the rock.

Geological Society of America Abstracts with Programs. Vol. 58, No. 1

doi: 10.1130/abs/2026SE-411869

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