The Minerva Slides in Soil Model

Slides in soil are downslope movement of soil under the influence of gravity, often triggered by intense rainfall or earthquakes. They can be slow or fast, and the failure can occur along planar, curved, and/or multiple surfaces. By mapping the distribution of previous landslides, surficial material type, surficial material texture, geomorphic processes, forest harvest, wildfire, road construction, and other terrain properties, it is possible to identify the slopes more susceptible to slides in soil. When slides in soil impact streams they can transform into debris flows.

For this study, we define a “slide in soil” model, intended as a conceptual abstraction of a slope described by the properties and the terms that a geoscientist may use to determine which slopes are more likely to fail and generate slides in soil. With slides in soil, we refer to the collective class from the updated Varnes classification (Hungr et al., 2014). It represents all landslides that have as material “soil” and movement type “slide”. It includes rotational, planar, compound, clay, silt, sand, gravel, debris slides. Table 1 summarizes the properties used to define the slides in soil model, drawn from the scientific literature (Evans and Clague, 1994; Friele, 2012; Guzzetti et al., 2012; Howes and Kenk, 1997; Hungr et al., 2014; Jackson et al., 2008; Jackson, 2019; Strahler, 1957)

Instance Property-Value-Frequency Model Definition Source Comments
has surficial material -Morainal Material (Till)-always Jackson et al 2008 Soil slides can be generated when morainal material fails from a slope
has surficial material -Bedrock-sometimes Jackson et al 2008 There may be some soil even when ‘bedrock’ has been mapped as principal surficial material
has surficial material -Colluvium-always Jackson et al 2008 Soil slides can be generated when colluvium has been mapped as principal surficial material
has geomorph process -ErosionalProcess-always guzzetti et al 2012 Active erosional processes are possible indicator of landslide activity, as landslides occur where landslides have occurred before.
has geomorph process -MassMovement-always guzzetti et al 2012 Active mass movement processes are possible indicator of landslide activity, as landslides occur where landslides have occurred before.
has slope -Plain-rarely Hungr et al 2014 Soil slides rarely occur on plain slopes.
has slope -Gentle-rarely Hungr et al 2014 Soil slides rarely occur on plain slopes.
has slope -Moderate-usually Hungr et al 2014 Soil slides usually occur on moderate slopes.
has slope -Moderately Steep-usually Hungr et al 2014 Soil slides usually occur on moderate steep slopes.
has slope -Steep-rarely Hungr et al 2014 Soil slides rarely occur on moderate steep slopes, because usually there is not much soil on steep slopes.
has slope -Very Steep-never Hungr et al 2014 Soil slides rarely occur on steep slopes, because usually there is not much soil on steep slopes.
has land use -Alpine-never Hungr et al 2014 Soil slides rarely occur in the Alpine zone, because usually there is not much soil there.
has land use -SubAlpineAvalancheChutes-usually Hungr et al 2014 Soil slides can occur in the gullies that are also avalanche tracks.
has stream order -1-always Hungr et al 2014, stream order concept from Strahler 1957, Stream erosion can cause soil slides
has stream order -2-always Hungr et al 2014, stream order concept from Strahler 1957, Stream erosion can cause soil slides
has stream order -3-usually Hungr et al 2014, stream order concept from Strahler 1957, Stream erosion can cause soil slides
has stream order -4-usually Hungr et al 2014, stream order concept from Strahler 1957, Stream erosion can cause soil slides
has stream order -5-sometimes Hungr et al 2014, stream order concept from Strahler 1957, Large stream erosion may cause soil slides
has transport line -Trail Skid-always Jackson 2019 Literature Review Trail skid are aggravating factor for landslide activity as compared to undisturbed slopes (Jackson 2019).
has transport line -Trail-sometimes Jackson 2019 Literature Review Trails are an aggravating factor for landslide activity as compared to undisturbed slopes (Jackson 2019)
has transport line -Road Resource-always Jackson 2019 Literature Review Logging roads are the greatest aggravating factor for landslide activity as compared to undisturbed slopes (Jackson 2019).
has transport line -Road Unclassified Or Unknown-always Jackson 2019 Literature Review Roads are an aggravating factor for landslide activity as compared to undisturbed slopes (Jackson 2019)
has transport line -Highway-rarely Jackson 2019 Literature Review Roads are an aggravating factor for landslide activity as compared to undisturbed slopes (Jackson 2019)
has transport line -Road Recreation Demographic-sometimes Jackson 2019 Literature Review Roads are an aggravating factor for landslide activity as compared to undisturbed slopes (Jackson 2019)
has thickness -Blanket-always Jackson et al 2008 Soil Slides can occur when there is enough soil that can be mobilized on a slope.
has thickness -Mantle of Variable Thickness-usually Jackson et al 2008 Soil Slides can occur when there is enough soil that can be mobilized on a slope.
has thickness -Veneer-sometimes Jackson et al 2008 Soil Slides can occur when there is enough soil that can be mobilized on a slope.
has thickness -Thin Veneer-rarely Jackson et al 2008 Soil Slides can occur when there is enough soil that can be mobilized on a slope.
has rainfall -Extreme Rainfall-always Friele 2012 Landslides can be triggered by intense rainfall (Segoni et al., 2018).  Rainfall threshold for this study are derived from Friele (2012).
has rainfall -Severe Rainfall-usually Friele 2012 Landslides can be triggered by intense rainfall (Segoni et al., 2018).  Rainfall threshold for this study are derived from Friele (2012).
has rainfall -Moderate Rainfall-sometimes Friele 2012 Landslides can be triggered by intense rainfall (Segoni et al., 2018).  Rainfall threshold for this study are derived from Friele (2012).
has rainfall -Mild Rainfall-rarely Friele 2012 Landslides can be triggered by intense rainfall (Segoni et al., 2018).  Rainfall threshold for this study are derived from Friele (2012).
has bed rock -metamorphic rock-always Friele 2012 Metamorphic foliated rocks have usually weak geotechnical properties. Basin underlain by these weak rocks are likely to experience more landslides compared to basin underlain by stronger lithologies (Bovis and Jakob 1999).
has texture -blocks-always Howes and Kenk 1997 The presence of block can be indicator of mass movement processes
has texture -rubble-always Howes and Kenk 1997 The presence of rubble is an indicator of mass movement processes.
has been logged within years ->20 years-sometimes Jackson 2019 Literature Review By 20 year since logging, trees have regrown and the roots are anchoring the soil again (Jackson 2019)
has been logged within years -10-20 years-usually Jackson 2019 Literature Review Landslides are likely by 10 to 20 years after tree harvesting as new trees are starting to provide anchoring effect with their roots on the slope (Jackson 2019)
has been logged within years -5-10 years-always Jackson 2019 Literature Review Landslides are extremely likely by 5 to 10 years after tree harvesting. Most of tree roots have died, and new trees are too small to provide anchoring effect with their roots on the slope (Jackson 2019)
has been logged within years -0-5 years-usually Jackson 2019 Literature Review Landslides are likely by 0 to 5 years after tree harvesting as the trees are dead but some roots are still providing anchoring effect on the slope (Jackson 2019)
has fire within years ->20 years-sometimes Jackson 2019 Literature Review After 20 year since a wildfire, trees have regrown and the wildfire effects on slope stability have diminished (Jackson 2019)
has fire within years -10-20 years-sometimes Jackson 2019 Literature Review Landslides are likely between 10 to 20 years after a wildfire. The roots have lost anchoring effect and the new trees are still too small to support the slope (Jakson 2019).
has fire within years -0-2 years-always Jackson 2019 Literature Review Landslides are very likely for 2 years after a wildfire. Water cannot infiltrate, runoff and erosion increase as the soil becomes water repellent and loses cohesion because of the fire heat (Jackson 2019). 
has fire within years -3-5 years-usually Jackson 2019 Literature Review Landslides are likely between 3 to 5 years after a wildfire. The water-repellent soil horizon degrades but the roots of dead trees are starting to rot and they do not support the slope with their anchoring effect anymore (Jackson 2019).
has fault -Any Fault-always Reichenbach et al 2018 The presence of fault is an important factor to determine landslide susceptibility
has fire within years -5-10 years-always Jackson 2019 Literature Review Landslides are very likely between 5 to 10 years after a wildfire. Roots of dead trees decay, and they are not supporting the soil anymore as for the case of tree harvesting logging (Jackson 2019).
has landslide type-Slides in soil-always Guzzetti et al 2012 Landslides are more likely to occur on slopes or valleys that have experienced landslides before.
has landslide type-Fall in rock-sometimes Guzzetti et al 2012 Where there is rock, it is less likely that there will be soil slides rather than landslides in rock. But landslides in rock are a sign of an unstable slope, and therefore are not explicitly negatively correlated to soil slides
has landslide type-Rock topples-sometimes Guzzetti et al 2012 Where there is rock, it is less likely that there will be soil slides rather than landslides in rock. But landslides in rock are a sign of an unstable slope, and therefore are not explicitly negatively correlated to soil slides
has landslide type-Flows in rock-sometimes Guzzetti et al 2012 Where there is rock, it is less likely that there will be soil slides rather than landslides in rock. But landslides in rock are a sign of an unstable slope, and therefore are not explicitly negatively correlated to soil slides
has landslide type-slides in rock-sometimes Guzzetti et al 2012 Where there is rock, it is less likely that there will be soil slides rather than landslides in rock. But landslides in rock are a sign of an unstable slope, and therefore are not explicitly negatively correlated to soil slides
has landslide type-Slope deformation in rock -sometimes Guzzetti et al 2012 Where there is rock, it is less likely that there will be soil slides rather than landslides in rock. But landslides in rock are a sign of an unstable slope, and therefore are not explicitly negatively correlated to soil slides
has landslide type-Spread in rock-sometimes Guzzetti et al 2012 Where there is rock, it is less likely that there will be soil slides rather than landslides in rock. But landslides in rock are a sign of an unstable slope, and therefore are not explicitly negatively correlated to soil slides

Table 1 The slides in soil Minerva Intelligence model. Model name, property, property value, information source and rationale are shown in the table

References

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Friele, P. A.: Volcanic Landslide Risk Management, Lillooet River Valley, BC: Start of north and south FSRs to Meager Confluence, Meager Creek and Upper Lillooet River., 2012.

Guzzetti, F., Mondini, A. C., Cardinali, M., Fiorucci, F., Santangelo, M. and Chang, K. T.: Landslide inventory maps: New tools for an old problem, Earth-Science Rev., 112(1–2), 42–66, doi:10.1016/j.earscirev.2012.02.001, 2012.

Howes, D. E. and Kenk, E.: Terrain Classification System for British Columbia., 1997.

Hungr, O., Leroueil, S. and Picarelli, L.: The Varnes classification of landslide types, an update, Landslides, 11(2), 167–194, doi:10.1007/s10346-013-0436-y, 2014.

Jackson, L., Smyth, C. and Poole, D.: Hazardmatch: an application of artificial intelligence to landslide susceptibility mapping, Howe Sound Area, Bristish Columbia, 4th Can. Conf. Geohazards From Causes to Manag., 594, 2008.

Jackson, L. E.: Recommendation for adding logging, logging road, wildfire, and morphometric parameters to the soil slide model., 2019.

Strahler, A. N.: Quantitative Analysis of Watershed Geomorphology, Transactions of the American Geophysical Union., Trans. Am. Geophys. Union, 38(6), 913–920, 1957.