2 Posters up all day Tuesday, Thursday, and 8 a.m. to noon Friday - Authors available Monday & Tuesday following the PM Oral Sessions

Monday, 20 June 2022
8:00 AM - 5:15 PM
Grand 'Ole Hall

NANOPARTICLES IN THE 2008 YANGJIAGOU ROCK AVALANCHE

Paper number: 2-6
Program: Sessions
Time: 8:00 AM – 5:15 PM

Authors

  • Mauri McSaveney Presenting Author
    SKLGP, Chengdu University of Technology, N/A
  • Wei Hu
    SKLGP, Chengdu University of Technology, N/A

Abstract

Our Yangjiagou rock avalanche fell into a valley called Yangjiagou, from the summit of Weijia Mtn (31° 58’ 01.68” N, 104° 34’ 47.3” E), triggered in the 2008 Wenchuan Earthquake. It buried an earlier rock avalanche probably triggered by a previous large earthquake (Wasowski et al. 2021). It also is a site of ongoing mitigation from repeated debris flows (Li et al. 2021). Since May 2008, the deposit has been deeply eroded in summer monsoon debris flows from floods from a lake dammed by the landslide. The 2008 rock avalanche has a volume of ~3.5 m3 but its contact with the older landslide of unknown age and volume is poorly defined and largely indistinguishable. Both came from a melange of pyrite-rich, black calcareous shale and travelled a similar path. We took 7 samples of sheared vein quartz and shale. To explore the effect of shear strain on grain-size distribution, we experimentally sheared quartz sand, and determined grain-size distributions after a range of different shear strains. Methods are discussed in Hu et al., (2021). We then determined fractal dimensions represented in our size gradings. Fractal dimensions from Yangjiagou suggested that the samples had undergone shear strains of 100–500% during emplacement: a rapidly progresssive brittle rock failure in about 100 s.

Hu W.; Xu, Q.; McSaveney M.; Huang R.; Wang Y.; Chang C.S.; Gou H. & Zheng Y. (2022) The intrinsic mobility of very dense grain flows. Earth and Planetary Science Letters, 580, 117389.

Li, Y., Hu, W., Wasowski J., Zheng, Y-S. & McSaveney, M. (2021) Rapid episodic erosion of a cohesionless landslide dam: Insights from loss to scour of Yangjia Gully check dams and from flume experiments. Engineering Geology 280.

Wasowski, J.; McSaveney, M.J.; Pisano, L.; Del Gaudio, V.; Li, Y. & Hu W. (2021) Recurrent rock avalanches progressively dismantle a mountain ridge in Beichuan County, Sichuan, most recently in the 2008 Wenchuan earthquake. Geomorphology 374.

Geological Society of America Abstracts with Programs. Vol. 54, No. 5

doi: 10.1130/abs/2022PR-376041

© Copyright 2022 The Geological Society of America (GSA), all rights reserved. Permission is hereby granted to the author(s) of this abstract to reproduce and distribute it freely, for noncommercial purposes. Permission is hereby granted to any individual scientist to download a single copy of this electronic file and reproduce up to 20 paper copies for noncommercial purposes advancing science and education, including classroom use, providing all reproductions include the complete content shown here, including the author information. All other forms of reproduction and/or transmittal are prohibited without written permission from GSA Copyright Permissions.