Empirical Landslide Modeling
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Transcript of Empirical Landslide Modeling
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Empirical Landslide Modeling
Finn Krogstad
UW Forest Engineering
May 30, 1990
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Overview
• Why Empirical Modeling?
• A simple example
• Logistic Regression
• Results
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Why Empirical Modeling?
• Most landslide models show where landslides will be, but not how many.
• If we want to evaluate operations or landscape plans, we need to know how many landslides will result from our plan.
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A simple example
Q: How many landslides will a high hazard area produced?
A: Count the fraction that have slid already, and apply this to the proposed action.
low mod high
No-cut pln=yln/nln pmn=ymn/nmn phn=yhn/nhn
clearcut plc=ylc/nlc pmc=ymc/nmc phc=yhc/nhc
hchcmcmclclc pNpNpNY
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Regression
• The familiar form
• can also be thought of as
• Allows any mapable variables of interest
• Already coded in ArcInfo
• Output in Probability of Landsliding
iharviroadicurveislopebasei harvaroadacurveaslopeaap exp1/1
iiii harvharv
roadroad
curvecurve
slopeslopebasei bbbbbp
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Hazard Mapping
• Using just slope and curvature, we can create a hazard map, much like SMORPH.
• This map can guide our design
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Operational Assessment
• Calculate cell probabilities before and after the operation, subtract, and sum the differences (E(ls)=.364).
before after difference
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Landscape Evaluation
• Same as the Operational evaluation, but on a larger scale.