Newman_GIS poster
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GIS Analysis of Landslides Near Rocky Mountain National Park, Colorado Connor Newman Department of Geological Sciences and Engineering GIS I Landslides are an important geomorphic process which have the capability to affect both human and natural systems. Landslides and other slope mass movements can be a9ributed to a number of factors including slope angle, aspect, and rock type. During September 2013 the Front Range area of Colorado received an extreme amount of rainfall, this precipitaGon and subsequent flooding caused numerous mass movements in the region. The area south of the town of Estes Park, on the edge of Rocky Mountain NaGonal Park was one of the most impacted areas. Numerous landslides occurred at a variety of scales , and the causaGve factors involved in these landslides has not yet been determined. IntroducGon Study Area Methods Results Conclusions References Cited Figure 1: Map of study area with Colorado map shown in inset. The current study area (seen in red on Figure 1 inset) is located on the northwestern extent of the Colorado Front Range (seen in blue on Figure 1), the most heavily populated area of Colorado. The study area contains three main lithologies with differing strength characterisGcs; granite, gneiss, and glacial driV. The study area also contains a wide variety of slope aspects and angles. GIS analysis was performed in order to determine what factors were associated with the majority of slope mass movements. GIS tools and skills uGlized were: digiGzing polygons; geodatabase feature class and feature dataset; aspect; slope; clip raster; mosaic raster; model builder; reclassify; raster to polygon; buffer line; and intersect. Number Area (km 2 ) % Area Total Landslides 21 0.648 N/A Landslide Sources 39 0.097 15 River 100 m Buffer 1 0.007 1.1 South Facing Sources 37 0.055 56 3060 Degree Slope Sources 37 0.068 70 Granite Sources 35 0.082 84 Glacial DriK Sources 2 0.005 5.2 Gneiss Sources 2 0.011 11 Figure 3: Processing example showing several layers created from DEM raster. Figure 2: Processing steps involved in idenTfying landslide mechanism. Figure 4: Map displaying complex nature and mulTple source points of landslides in north St. Vrain Canyon. Results from GIS analysis has idenGfied the primary causes of all 21 landslides idenGfied in the study area. Results show that landslides commonly have mulGple source areas, can be sourced from mulGple lithologies, and can display complex geometries. Findings of probable causes for landslides are summarized below. South facing slopes and slopes between 30 and 60 degrees contained the same number of landslide source areas, though source areas on 3060 degree slopes were larger. Granite is the lithology which most commonly contributes to landslides. Granite also made up the largest percentage of landslide source area. Proximity to rivers was not a major cause of landslides. Figure 5: Large landslide on Twin Sisters Mountain sourced from a combinaTon of granite and gneiss. Lan, H., Derek MarTn, C., & Lim, C. H. (2007). RockFall analyst: A GIS extension for threedimensional and spaTally distributed rockfall hazard modeling. Computers & Geosciences, 33(2), 262–279. doi:10.1016/ j.cageo.2006.05.013 Stock, G. M., Bawden, G. W., Green, J. K., Hanson, E., Downing, G., Collins, B. D., … Leslar, M. (2011). HighresoluTon threedimensional imaging and analysis of rock falls in Yosemite Valley, California. Geosphere, 7(2), 573–581. doi:10.1130/GES00617.1 Stock, G., Collins, B., Santaniello, D., Zimmer, V., Wieczorek, G., Snyder, J. (2013). Historical Rock Falls in Yosemite Na;onal Park , California (pp. 1–17).
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Transcript of Newman_GIS poster
GIS Analysis of Landslides Near Rocky Mountain National Park, Colorado Connor Newman
Department of Geological Sciences and Engineering GIS I
Landslides are an important geomorphic process which have the capability to affect both human and natural systems. Landslides and other slope mass movements can be a9ributed to a number of factors including slope angle, aspect, and rock type. During September 2013 the Front Range area of Colorado received an extreme amount of rainfall, this precipitaGon and subsequent flooding caused numerous mass movements in the region. The area south of the town of Estes Park, on the edge of Rocky Mountain NaGonal Park was one of the most impacted areas. Numerous landslides occurred at a variety of scales , and the causaGve factors involved in these landslides has not yet been determined.
IntroducGon
Study Area
Methods
Results
Conclusions
References Cited
Figure 1: Map of study area with Colorado map shown in inset.
The current study area (seen in red on Figure 1 inset) is located on the north-‐western extent of the Colorado Front Range (seen in blue on Figure 1), the most heavily populated area of Colorado. The study area contains three main lithologies with differing strength characterisGcs; granite, gneiss, and glacial driV. The study area also contains a wide variety of slope aspects and angles.
GIS analysis was performed in order to determine what factors were associated with the majority of slope mass movements. GIS tools and skills uGlized were: digiGzing polygons; geodatabase feature class and feature dataset; aspect; slope; clip raster; mosaic raster; model builder; reclassify; raster to polygon; buffer line; and intersect.
Number Area (km2) % Area
Total Landslides 21 0.648 N/A
Landslide Sources 39 0.097 15
River 100 m Buffer 1 0.007 1.1
South Facing Sources 37 0.055 56
30-‐60 Degree Slope Sources 37 0.068 70
Granite Sources 35 0.082 84
Glacial DriK Sources 2 0.005 5.2
Gneiss Sources 2 0.011 11
Figure 3: Processing example showing several layers created from DEM raster.
Figure 2: Processing steps involved in idenTfying landslide mechanism.
Figure 4: Map displaying complex nature and mulTple source points of landslides in north St. Vrain Canyon.
Results from GIS analysis has idenGfied the primary causes of all 21 landslides idenGfied in the study area. Results show that landslides commonly have mulGple source areas, can be sourced from mulGple lithologies, and can display complex geometries. Findings of probable causes for landslides are summarized below.
-‐South facing slopes and slopes between 30 and 60 degrees contained the same number of landslide source areas, though source areas on 30-‐60 degree slopes were larger. -‐Granite is the lithology which most commonly contributes to landslides. Granite also made up the largest percentage of landslide source area. -‐Proximity to rivers was not a major cause of landslides. Figure 5: Large landslide on Twin Sisters Mountain
sourced from a combinaTon of granite and gneiss.
Lan, H., Derek MarTn, C., & Lim, C. H. (2007). RockFall analyst: A GIS extension for three-‐dimensional and spaTally distributed rockfall hazard modeling. Computers & Geosciences, 33(2), 262–279. doi:10.1016/j.cageo.2006.05.013
Stock, G. M., Bawden, G. W., Green, J. K., Hanson, E., Downing, G., Collins, B. D., … Leslar, M. (2011). High-‐resoluTon three-‐dimensional imaging and analysis of rock falls in Yosemite Valley, California. Geosphere, 7(2), 573–581. doi:10.1130/GES00617.1
Stock, G., Collins, B., Santaniello, D., Zimmer, V., Wieczorek, G., Snyder, J. (2013). Historical Rock Falls in Yosemite Na;onal Park , California (pp. 1–17).
