Which is more susceptible to landslide based on lithology compared to one another? Granite, Conglomerate, Sandstone, Mudstone

I've been tasked to create a hazard map and was given a Geologic Map, Rainfall Map and Topographic Map. This question mainly pertains to the Geologic Map. How do these 4 different lithologies compare their proneness to landslide against one another?

I have done some searching and still am not sure of which is more prone against the other.

This is an excerpt from here: https://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=2632&context=icwdm_usdanwrc

"Granite (an igneous rock) is one type of parent material that, when weathered, results in relatively high slope instability, as found on landslides in Korea (Wakatsuki et aI., 2005) and Nepal (Ibetsberger, 1996). The instability of granite rocks probably results from relatively slow weathering, which produces shallow soils with low water storage and high permeability (Sidle & Ochiai, 2006).

Weak sedimentary rocks, such as mudstone and shale, are also highly susceptible to landslides (Pearce & O'Loughlin, 1985; Chigira & Oyama, 1999). The presence of particular compounds and oxidation in sandstone (another sedimentary rock) determines if it is weakened and therefore more susceptible to landslides, or if it is strengthened by cementation by iron oxide or hydroxide (Chigira & Oyama, 1999)."

My guess,for now, is: Mudstone > Sandstone > Granite > Conglomerate

I have not found any source for conglomerate though. I'm mostly just basing this off of the rock's resistance to weathering.

  • 1
    $\begingroup$ your problem is those 3 sediments vary wildly in properties. I have worked mudstone so hard and tough it blunts steel chisels after a few strikes and others you can cut with a knife. these materials have highly variable properties. $\endgroup$
    – John
    Dec 28, 2021 at 5:41


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