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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

• Hydrology – Watersheds– Rivers– Gage stations– FEMA flood maps

Data

•• 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

Analysis

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3rd Cross-Section in Eastern Tacoma

Analysis