1983 Sale Mountain landslide, Gansu Province, China

Zhang, Zhuoyuan; Chen, Shang-Ming; Tao, Lianjin

doi:10.1130/reg15-p149

Cited by 14 publications

(17 citation statements)

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“…In flows dominantly fed by fine‐grained material such as sand or mud, original or secondary cohesion as that described by Shea and Van Wyk de Vries () may be enough to produce molards. It is possible that molards described and portrayed for the Sale Mountain slide that was sourced by a thick, semi‐cohesive loess succession (Zhang et al , ) had its origin related to secondary cohesion because slickensides were described on the sides of the cones. The revision of all areas of molard occurrence using Gruber's () global permafrost model (Table ) also suggests that the Sale Mountain molards were not associated with permafrost.…”

Section: Discussionmentioning

confidence: 99%

“…Molards have been mentioned on the Khait slide , the Yigong rock and debris avalanche (Qiang et al, 2012) and the Sale Mountain landslide (Zhang et al, 2002) in Asia, while in North America they have been reported in the Frank slide (McConnell and Brock, 1904;Cassie et al, 1988), the Sherman slide, just as 'cones' (Marangunic and Bull, 1968) and 'xenolithologic debris cones' (Shreve, 1968, page 400), the Little Salmon Lake landslide (Brideau et al, 2010) and the Pink Mountain slide (Geertsema et al, 2006) (Table 1). Undocumented molards are probably present in many other landslide deposits.…”

Section: Molard Occurrencementioning

confidence: 99%

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Molards and Their Relation to Landslides Involving Permafrost Failure

Milana

2015

Permafrost & Periglacial

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Molards are conical‐shaped, often symmetrical debris mounds with a distinctive radial grain size gradation, which were first named in the Alps over 100 years ago. Historically, these landforms did not receive much academic attention as they were rarely observed. Today, six different genetic hypotheses can be applied to molards, and the most recent has suggested a link to permafrost failure. The aim of this research was to test the hypothesis that molards result from the failure of permafrost‐bearing ground and subsequent thawing of the frozen debris boulders. This hypothesis is tested by: (1) reviewing the known global distribution of molard‐bearing mass movements with respect to permafrost distribution; (2) investigating a landslide in the Andes of Argentina that unequivocally relates to permafrost failure; (3) describing and interpreting the external and internal structure of molards, applying sedimentary transport concepts; and (4) reproducing molards by laboratory simulation. The results show that, with few exceptions, molards are produced by melt‐out of ground ice in permafrost blocks. In particular, a permafrost source of the mass flow is more certain for landslide deposits that are densely populated by molards. This study serves to reappraise the presence of molards as they could be used to track ground ice loss and potential permafrost degradation in mountainous areas and hence climate change. Copyright © 2015 John Wiley & Sons, Ltd.

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Section: Discussionmentioning

confidence: 99%

Section: Molard Occurrencementioning

confidence: 99%

Molards and Their Relation to Landslides Involving Permafrost Failure

Milana

2015

Permafrost & Periglacial

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“…We consider a decaying time‐dependent boundary condition An observer sitting in the Valles Marineris canyon at x = 0, some small distance from the source wall, would see an instantaneous rise in flow thickness when the flow reaches his station followed by an exponential decay with some time constant T . Such a boundary condition is suitable for debris flows [e.g., Iverson , 1997], or long‐run‐out landslides [e.g., Campbell et al , 1995; Davies et al , 1999; Zhang et al , 2002; Harrison and Grimm , 2003].…”

Section: Quantitative Inferences On the Mechanics Of Emplacementmentioning

confidence: 99%

Comparing landslides to fluidized crater ejecta on Mars

2005

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[1] We use the Mars Global Surveyor and Viking data sets to compare and contrast the geomorphology of four large Martian landslides located in Valles Marineris to fluidized ejecta of seven fresh Martian craters located in Lunae Planum. Both mass movements have flowed over the Martian surface and possess characteristics seen in terrestrial mass movements. We combine these comparisons with simple flow models to determine how the planar geometry of landslides and the cylindrical geometry of ejecta can generate different topographic expressions for the same input constraints. Our purpose is to better understand the emplacement processes of both types of mass movements. Our geomorphic analyses are consistent with previous views that the large Martian landslides resemble large terrestrial long-run-out flows. The planar flow model supports this inference: Martian landslides probably flowed as a basal glide, where motion is limited to a narrow interface at the base of the mass movement. Geomorphic investigations of fresh multilayered ejecta indicate that their inner portions with their subtle rampart probably flowed like their landslide counterparts as a basal glide. Distal pronounced contiguous ramparts, however, resemble features akin to terrestrial debris flows. The cylindrical flow model shows that differences in geometry can mask the dynamics of flow emplacement. This model suggests, as expected, a basal glide origin for the inner portions of the ejecta. Surprisingly, basal glide also best explains the topography of the distal ejecta ramparts.

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“…Figure 2 shows a simplified stratigraphic and topographic section of the pre-landslide topography and the Saleshan landslide along its main sliding direction. The presented stratigraphic and topographic section is modified after the previous version from Zhang and Wang (1984) and Zhang et al (2002). The geological structures can be referred to in previous studies (Wu & Wang, 2006;Zhang et al, 2002;Zhang & Wang, 1984).…”

Section: Geological Structuresmentioning

confidence: 99%

“…The presented stratigraphic and topographic section is modified after the previous version from Zhang and Wang (1984) and Zhang et al (2002). The geological structures can be referred to in previous studies (Wu & Wang, 2006;Zhang et al, 2002;Zhang & Wang, 1984).…”

Section: Geological Structuresmentioning

confidence: 99%

A catastrophic flowslide that overrides a liquefied substrate: the 1983 Saleshan landslide in China

Zhang

Peng

Gao

et al. 2021

Earth Surf Processes Landf

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Flowslides that override a liquefied substrate can vastly enhance a disaster after failure initiation. These effects may result from the rapid velocity and long runout distance from slides mobilized into flows. It is thus crucial to provide an improved understanding of the transformation mechanisms of catastrophic flowslides for hazard evaluation. This study examines the Saleshan landslide in Gansu, China, which occurred in 1983 and killed more than 200 people. The Saleshan landslide travelled for approximately 1 km due to pore water pressure generation resulting from overrunning and liquefication of the alluvial sands in the river valley below. We used geomorphologic and topographic maps to determine its dynamic features and mobilization behaviors on the landslide body, and placemarks and seismic signals to identify its approximate velocity at different sites. Electrical resistivity tomography (ERT) surveys also revealed the hydrogeological conditions post-landslide, showing a clear groundwater table along with the liquefied alluvial sand and gravel layers. Particle size distributions and triaxial shear behaviors confirmed more ready liquefaction of superficial loess and underlying alluvial sand in comparison with the red soil above and below them. Novel loading impact triaxial testing was also performed on the alluvial sand to elucidate its liquefaction potential in undrained and drained conditions.The alluvial sand was found to be markedly prone to liquefaction in undrained conditions due to impact-induced increased pore water pressure. The results further demonstrated that the Saleshan landslide underwent a transformation from a slowing slide on a steep slope, where it originated, to flow on a nearly flat terrace with abundant groundwater that it overrode. The transformation mechanism involved the liquefied alluvium sand substrate, which greatly enhanced the landslide mobility. Along with recent, similar findings from landslides globally, substrate liquefaction may result in a widespread, significant increase in landslide mobility and thus hazard, and the present study identifies the requisite conditions for this phenomenon to occur.

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1983 Sale Mountain landslide, Gansu Province, China

Cited by 14 publications

References 0 publications

Molards and Their Relation to Landslides Involving Permafrost Failure

Molards and Their Relation to Landslides Involving Permafrost Failure

Comparing landslides to fluidized crater ejecta on Mars

A catastrophic flowslide that overrides a liquefied substrate: the 1983 Saleshan landslide in China

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