gis landslides analysis ii
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GIS LANDSLIDES ANALYSISRoadway between USC Wrigley Institute and Two Harbors
Catalina Island, CA.
M.Sc. GIS Program – GEOG 587 class
Presented by: Edmundo M. Zevallos
April 3rd. 2011
GIS LANDSLIDES ANALYSIS
A Landslide is a Mass movements under influences of gravity.
Roadway between USC Wrigley Institute and Two HarborsCatalina Island, CA.
A Landslide is a Mass movements under influences of gravity. Occurs as a result of diverse disturbing and destabilizing
processes, for example of climatic or anthropological origin. The stability of slopes is determined by the geometry of surfaces
and slip-horizons.
Introduction
p
In regard to spatial landslide analysis, GIS is an important tool to carry out data input, handling, visualization, combination, query, analysis.
Ability of the GIS to incorporate the spatially varying data of Hypothesis:
Ability of the GIS to incorporate the spatially varying data of ground elevation, soil properties, slope, etc. in the engineering analysis of the slope stability.
USC MARINE CAMPUS-TWO HARBORS GIS LANDSLIDES ANALYSIS
Roadway between USC Wrigley Institute and Two Harbors
ROADWAY• An analysis of landslide in an specific area of the Catalina Island.
• Study Area located in the north west part (section third) of the island
Catalina Island, CA.
• Study Area located in the north west part (section, third) of the island.
• In the East-West existing roadway between the USC Wrigley Institute facility and the town of Two Harbors.
Research following a spatially-distributed data with a geo-reference to real world.
USC Wrigley Institute
ExistingRoadway
Area of Analysis
Two Harbors
y
GIS LANDSLIDES ANALYSIS
Raster-based GIS was applied in order to analyze the spatial distribution of landslides
Roadway between USC Wrigley Institute and Two HarborsCatalina Island, CA.
distribution of landslides. Parameters established in a map: 1.- slope
2.- Geology3.- Geomorphology4.- drainage/scour network5.- Road network
Four possible landslides spot were inventoried in the study. Followed by a field work inventory in the North East side of the
existing roadway. Three types of landslides were identified in the study area
Abstract
Three types of landslides were identified in the study area1.- scour2.- rock falls3.- flows
The landslides are distributed:1 id f l (15% t 50%) di t ( f 1)1.- on a wide range of slope (15% to 50%) gradient (ref.1)2.- Two constant geological (ref 2) setting: - Catalina Schist
- Volcanic. This paper will demonstrates the ability of the GIS to incorporate
the spatially varying data of: - ground elevation, soil properties, etc. p y y g g , p p ,in the engineering analysis of the slope stability.
GIS LANDSLIDES ANALYSIS
The management of spatial-data is pivotal for this analysis, due:
Roadway between USC Wrigley Institute and Two HarborsCatalina Island, CA.
1. - The unique capability of GIS: to workTo captureTo store
Manage the data 2. - The handle of data referenced: by vast spatial
O hi di t
GIS and Landslide analysis
Or geographic coordinates
3. - Its ability to incorporate appropriate engineering models
In the case of the landslide analysis in here, this analysis demands:1. - Collection of data, 2. - Storage of data 3 Use of the data for the analysis handled in the GIS3. - Use of the data for the analysis handled in the GIS environment.
GIS LANDSLIDES ANALYSISRoadway between USC Wrigley Institute and Two Harbors
Catalina Island, CA.
GIS LANDSLIDES ANALYSISRoadway between USC Wrigley Institute and Two Harbors
Catalina Island, CA.
GPS device Reported Number of Description
Collection of data
GPS device Reported accuracy
Number of points taken
Description of points
Nomad (Trimble)
5 mt 5 points Drainage Structures and Possible Slide
GPS devices were used and their
of dataland location
630 pointGPS Setup to logging
results different accuracy.
interval every 5 seconds2,120 pointsGPS setup to logginglogging interval every 1 meter
Geo XH (Trimble)
45 cm 18 points( )
GIS LANDSLIDES ANALYSISRoadway between USC Wrigley Institute and Two Harbors
Catalina Island, CA.
Storage of data and processingArcMap Layers:
ArcMap storage of Data and analysis
spatially-distributed data and geo-reference to real world.
g y
Critical area along road
+
Typical Drainage structure
Typical possible Landslide spot
GIS LANDSLIDES ANALYSISRoadway between USC Wrigley Institute and Two Harbors
Catalina Island, CA.
GPS Pathfinder OfficeCreation of Data Dictionary editor
Dat
a C
olle
ctor
de
vice
Creation of Data Dictionary editor
ArcMap storage of Data and spatial analysis
Storage of data and processing
(cont.)
Sratigraphy thickness
Thickness
Slope
US Geological SurveyMetadata of Catalina Island
521
poly
gons
4,
GIS LANDSLIDES ANALYSISRoadway between USC Wrigley Institute and Two Harbors
Catalina Island, CA.
F l ti f T i l l d lid l i
A slope stability analysis combined with risk
Formulation of Typical landslide analysis
A slope stability analysis combined with risk analyses is proposed to carry out.
The area under investigation is geoprocessed in ArcMap, and marked with more than 4,000 point elevationselevations.
It could observe that the hill is sloping downward towards northwest.
The slide has occurred at the upper regions.
Various man-made features are also present, like roads and only three drainage structures, a
t f lli i th d lstream falling in the downslope.
GIS LANDSLIDES ANALYSISRoadway between USC Wrigley Institute and Two Harbors
Catalina Island, CA.
Formulation of Typical landslide analysis (cont.)
The steps involved in the landslide hazard it generates a mapping given as flow chart.
The formulation of the work is described.
The methodology gyproposed would be able to develop the hazard map, and perform decision analysis
GIS LANDSLIDES ANALYSISRoadway between USC Wrigley Institute and Two Harbors
Catalina Island, CA.
ColoredContours Triangles ColoredTriangles surfaces
DTMDigital Terrain ModelModel
Plan View of Existing RoadPlan View of Existing Road
Profile of Existing Road
GIS LANDSLIDES ANALYSISRoadway between USC Wrigley Institute and Two Harbors
Catalina Island, CA.
Conclusions
1) I studied the distribution / characterization of landslides in the study area through: - Photointerpretation- Geomorphologic surveyGeomorphologic survey
2) This area of study is characterized by two stratigraphic-structural units: - Mostly Miocene volcanic rocks- Tertiary subvolcanic rocks- Tertiary subvolcanic rocks
3) This research shows that in the area of the analysis there are two types of landslides: - slow earth flow their landslide masses are quite small
k f ll i li t f ti- rock falls occur in limestone formations
4) Morphometric characteristics, play an important role in landsliding processes.
5) Can be determined through the analysis of the digital terrain model.
GIS LANDSLIDES ANALYSISRoadway between USC Wrigley Institute and Two Harbors
Catalina Island, CA.
Conclusions (cont.)
6) The application of this method would be useful to locate potential unstable areas, and so to predict the occurrence of future landslides.
7) Since the slides has occurred at the upper regions and hence short-term remediation will be an immediate solution in the form of relief wells.
8) The analysis using: - Hydrologic models could be incorporated in the Arc View- Stability models
9) GIS-based techniques are the best approach to the study of landslide tibilit b th ll th t f l th isusceptibility because they allow the management of several themes concerning
instability factors.
10) Geographic Information Systems (GIS) is being exploited widely in many engineering problems which involves spatial data managementengineering problems, which involves spatial data management.
GIS LANDSLIDES ANALYSISRoadway between USC Wrigley Institute and Two Harbors
Catalina Island, CA.
Thank you for your attention
Any questions?
GIS LANDSLIDES ANALYSISRoadway between USC Wrigley Institute and Two Harbors
Catalina Island, CA.
References
Soil Survey of Catalina Island, California. USDA (2008) USGS - Soils data for the Conterminous United States
Derived from the NRCS State Soil Geographic (STATSGO) D t B (2001)Data Base. (2001)
Landslide analysis in Geographic Information Systems, G.L. Babu (1998)
Soils data for the Conterminous United States Derived from Soils data for the Conterminous United States Derived from the NRCS State Soil Geographic (STATSGO) Data Base. (1995) USGS.
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