1 Risk Assessment of Mount Rainier Lahars on Urban Populations Mark Gibson, Chris Long, Michael Hekkers Mark Gibson, Chris Long, Michael Hekkers Portland State University Portland State University December 4, 2007 December 4, 2007 Lahar Definition • Definition- Indonesian word mudflow composed of water and volcanic ash (80% solid material by weight). 1 . • Triggered by the flash melting of the snow cap of a volcanic mountain or from heavy rain. 2 • Travels at great speeds. Marabaix et al, 2007; Geology.com Marabaix et al, 2007; Geology.com (Photo by Lyn Photo by Lyn Topinka Topinka, USGS) , USGS) Mount St. Helens, 1980 Lahar History Scott and Valance, 1995 • Peak was 600 m (2000 ft) higher?
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Risk Assessment of Mount Rainier Lahars on Urban
Populations
Mark Gibson, Chris Long, Michael HekkersMark Gibson, Chris Long, Michael HekkersPortland State University Portland State University
December 4, 2007December 4, 2007
Lahar Definition
• Definition- Indonesian word mudflow composed of water and volcanic ash (80% solid material by weight).1.
• Triggered by the flash melting of the snow cap of a volcanic mountain or from heavy rain.2
• Travels at great speeds.
Marabaix et al, 2007; Geology.comMarabaix et al, 2007; Geology.com
(Photo by LynPhoto by Lyn TopinkaTopinka, USGS), USGS)
Mount St. Helens, 1980
Lahar History
Scott and Valance, 1995
• Peak was 600 m (2000 ft) higher?
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Hoblitt, 1995
Residential Growth 1990-2000
• Pierce County 114,615 residents• Thurston County 46,117 residents• King County 229,741 residents
Questions for Database
1. Calculate population affected by lahar2. Calculate population volumes on
identified evacuation routes 3. Calculate potential lahar depth and
compare to existing data
Data• Lahar Hazard Zones• 30m DEM of Washington State• Mount Rainier National Park
– Glaciers shapefile– 10 m DEM and DOQ– Park Roads– Park Trails
•• Compilation of DataCompilation of Data–– U.S. Census Block DataU.S. Census Block Data
•• King King •• PiercePierce•• ThurstonThurston
–– Washington State RoadsWashington State Roads•• InterstatesInterstates•• HighwaysHighways•• ArterialsArterials•• Secondary roadsSecondary roads
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Reduction of Data Redundancy(Normalization)
• Shapefile tables are full of redundant data
Reduction of Data Redundancy• Redundant fields in the Shapefiles can be
removed and put into attribute tables to give more tables with less data
Lahar Feature Dataset•Consists of
•Lahar Hazard Zone•Gage Stations•County Boundaries•Lahar Definitions•Merged CountyCensus Data
•Census Tables
Topology RulesLahar TopologyRules
•Based on counties,census blocks
•Created to ensurecensus block werecorrect with the counties
Population
• Consists of – Census data for King,
Pierce, and Thurston counties
– Thiessen Polygons
Population
• Created ThiessenPolygons from block centroids
• Found Centroids of the ThiessenPolygons
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Data Query
2. Roads• Data Consists
of:– Washington
roads– Roads
definition table– Tables based
on analysis• Population
near feature id
3. Lahar Depth CalculationsLahar Volume
17.46~Crater Lake (for comparison)
15.4311.224.21**All Mount Rainier Glaciers
4.693.411.28**Emmons & Winthrop
Total volumeKm3
*Solids volumekm3
Water Volume km3Feature Name
* Approximately 80% of a lahar volume is estimated to be solids.
*Marabaix et al, 2007; **Nylen 2004
Depth Data
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DataMt. Rainier Summit 14,410ft
Puget Sound
Elevation = 0ft
Modeling
Lahar Ending at Puget Sound Lahar on Mt. Rainier
Modeling
Lahar extent
Ridgeline
Modeling
Modeling Modeling
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• Data Storage is accomplished through the use of “flat” files (ASCII and binary), as well as the HEC-DSS. User input data are stored in flow files under separate categories of project, plan, geometry, steady flow, unsteady flow, and sediment data. Output data is predominantly stored in separate binary files. Data can be transferred between HEC-RAS and other programs by utilizing the HEC-DSS
Modeling
Analysis Analysis
3D Analyst 1283m~ 4,209ft.
921m ~ 3,021ft.
1149m~ 3,976ft.
Width = 4,866ft
~.921miles
4,209ft. + 3,976ft/2 – 3,021ft. =
Depth of Lahar at cross section
1071ft.
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697m~ 2,286ft.
585m ~ 1,919ft.
699m~ 2,293ft.
Width = 9,044ft
~1.71miles
2,286ft. + 2,293ft/2 – 1,919ft. =
Depth of Lahar at cross section
370ft.
159m~ 521ft.
93m ~ 301ft.
159m~ 521ft.
Width = 36,091ft
~6.83miles
521ft. + 521ft/2 – 301ft. =
Depth of Lahar at cross section
151ft.
Answers
1. Population affect > 215,000
2. Road evacuation densities up to 18,000 on secondary roads
Conclusions
• Database diagramming-– necessary for construction and modification
• PGDB- useful for projection consistency (limited user access)– Relationship classes – special attention to
tables• SQL queries
– Topology- data integrity
Limitations and Future Work
• Limitations– Census– Lack of evacuation routes
• Future work– Future population growth – Dasymetric mapping with land use– File geodatabase and new database software– Flood software and lahar raster DEM
References• Arctur, D., Zeiler, M. 2004. Designing Geodatabases case studies in GIS Data Modeling p.
76-79• Crandell, D.R. 1969. Surficial Geology of Mount Rainier National Park Washington, Geological
Survey Bulletin 1288 p. 22-26. • Geography Network Services Hosted by ESRI • HEC-RAS, US Army Core of Engineers http://www.hec.usace.army.mil/software/hec-ras/• Hoblitt, R.P., Walder, J.S., Driedger, C.L., Scott, K.M., Pringle, P.T., and J.W. Vallance, 1995.
Volcano Hazards from Mount Rainier, Washington: U.S. Geological Survey Open-File Report 95-273.
• Marabaix, P., Nicholls, R. J., 2007. Breakout Lahar from New Zealand’s Crater Lake. EOS. Vol. 88, 243: 442- 443.
• Nylen, T. 2004. Spatial and Temporal Variations of Glaciers on Mount Rainier between 1913 and 1994, Master’s Thesis, Portland State University.
• Scott, W. and J. W. Vallance. 1995. Debris Flow, Debris Avalanche, and Flood Hazards At and Downstream from Mount Rainier, Washington: Hydrologic Investigations Atlas HA-729.
• US Geological Survey Stream Gageshttp://waterdata.usgs.gov/wa/nwis/current/?type=flow
• Washington Office of Financial Management http://www.ofm.wa.gov/geographic/00tiger.asp
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Questions
• http://www.youtube.com/watch?v=N_cyG2dJPpc
http://proximityone.com/tgrcfcc.htm
Nylen 2004
Data Data
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Data Data
Modeling Analysis
1st Cross-Section near summit of West Fork of the White River
Analysis
2nd Cross-Section at the confluence of the East and West Forks of the White River