Saturday, May 23, 2015

GIS Applications: Lahars

Hello and welcome to my inaugural post in my GIS Applications course. This begins a look at how GIS can be used to plan for and react to natural environmental hazards. This week's topic of focus is Lahars. Lahars are volcanic debris flows consisting of ash, soil, water which can be either super heated or cool,  and travel through river ways and natural ravines from some volcanic eruptions. The study area for the lab was Mt Hood in Oregon. The objectives of this lab were to conduct a hydrology analysis to define river ways most likely to channel Lahar activity, and identify the local populations inhabiting the most likely areas to be affected. All base data was provided by UWF, and assembled in ArcMAP.


The map above depicts the Mt Hood region in Oregon and highlights block groups that at least partially intersect or fall within 1/2 mile of the river areas stemming from Mt Hood. These are colored yellow for lower population concentration to red where the highest population per block group occur. These river areas would channel lahar activity which could devastate the areas around the river as they carried tons of debris down from the mountain. ArcMAP hydrology and raster tool sets needed to be used to generate the river ways seen, by starting with a digital elevation model, and identifying where the natural water channels are, and overall flow directions. This determined where lahar activity would likely occur and allowed the population groups affected to be identified. In addition to highlight population by block group, the schools within 1/2 mile of the river ways are also highlighted and labeled. Thank you for viewing my map.
Check back for more posts as the course goes on.

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