Using ModelBuilder Landslide Susceptibility

1
Using ModelBuilder Landslide Susceptibility

• Ann Johnson

2
Modeling Landslides

• What factors influence landslides?
• What data can be used to model landslides
  susceptibility and what are we going to use?
• What analyses can suggest probabilities of
  landslides?
• What is ModelBuilder and how can it be used to
  model landslides
• How can the results be visualized in 3D

3
Landslide Susceptibility steep mountain slopes,
faults, climate
4
Add Fires
5
3D View of burned area
6
Factors Influencing Landslide Susceptibility

• Slope steeper more susceptible
• Aspect South facing dry, little vegetation
• Burn Severity least vegetation as severity of
  burn increases and creating hydrophobic soil
• Weigh each outputs affect to determine areas
  with highest susceptibility

7
Basic Data Sets for Our Model

• Raster
• Elevation data (DEM)
• Continuous data set with each center of a grid
  containing the value for the elevation (10 x 10 m
  grid, Z in meters)
• Digital Raster Graphic of study area
• Vector
• Severity of burn
• Road, streams, faults, geology, historic
  landslides
• Vector to Raster Conversion
• Severity of burn from Vector (polygon) to raster

8
Faults Layer
Streams Layer
Landslide Layer
Roads Layer
DEM Layer
Four Vector and One Grid Data Layers
9
DEM - Raster
Properties of elevation layer
10
Geology Old Slides
11
Grids Layers can be Combined - binary
suitability models

• Use for simple problems
• Map Algebra or Boolean And Tools
• Classify layers into good (1) and bad (0)
• Combine with AND, addition or multiplication
• ski snow slope sun
• Advantages
• Easy
• Disadvantages
• No nextbest sites
• All layers have same importance
• All good values have same importance

12
Using Tools in ArcToolbox one by one
13
Spatial Analyst Surface Hillshade To shade
and make elevation look 3D
14
Spatial Analyst Surface Slope To determine
slope from elevation
15
Spatial Analyst Reclass Reclassify Slope To
determine the Angles of the Slope
16
Conversion To Raster Feature to Raster To
Convert burn Polygon to Raster
17
Weighted suitability models

• Use for complex problems
• Overlay tool from Spatial Analysis Toolbox
• Classify layers into suitability 1-9 (9 best)
• Weight and add together
• Ski (snow .5) (slope .3)
  (sun .2)
• Advantages
• All values have relative importance
• All layers have relative importance
• Returns suitability on a scale 1-9
• Disadvantages
• Preference assessment is harder

18
Spatial Analyst Overlay Weighted Overlay To
use relclassified Slope, Aspect, and Burn
Severity datasets and weigh effect of Slope most
19
Finals Output Possible Slide Areas
20
Automating Analysis ModelBuilder
. . . And Shared
21
Landslide ModelBuilder
22
3-D Analyst ArcScene
23
Now in two parts

• Part I
• Introduce data and ArcCatalog
• Understand the location of the data (photos)
• Look at a Landslide data sets
• Use tools in ToolBox one at a time to do analysis
• Part II
• Use ModelBuilder and build a Model
• Use results and create an ArcScene project and
  create a fly through animation