1. Suggest how the National Park boundary for Mount Rainier has been influenced
ID: 291172 • Letter: 1
Question
1. Suggest how the National Park boundary for Mount Rainier has been influenced by the extent of small lahars, lava flows and pyroclastic flows.
2. Lahars travel down river and stream valleys. What problem does this cause for evacuation of the towns Puyallup, Carbon and White River valleys?
3. The estimated travel time for a large lahar to reach the town of Orting is around 40 minutes. What then is the average speed of a large lahar? What do you think happens to the speed of a lahar as it flows down the Puyallup River valley?
4. Use the average lahar speed you calculated to figure out how long a large lahar would take to travel from Orting to Puyallup.
5. The maximum ‘height’ of a lahar is 100 feet. Knowing this, what is the best evacuation advice you could give to a citizen of Orting?
Enumclaw te River Buxcley King Greennater Mud WakesonMountain Pierce arbonado Graham 2 n River allup R nt Rainier National ParkEoundary Kapowsin MOUNT RAINIER Thurston County River Thurston County Lewis County Ashford EXPLANATION Small lahars with recurrence Moderate lahars withrecurrence Large lahars with tecurrenoe Nea most likely be affected by intervalExplanation / Answer
ANSWER-
1.) The effect of lahars ,lava flows and pyroclastic flows with a volume of 270 cubic kms since the last 1 milion years seems to have affected more on the mountains and its nearby areas,few miles away from the base.Such volcanism in the past had led to deposition of thick volcanoclastics to the west of the mountain in addition to forming shield on the dissected surfaces of the basement rocks.Also the area inundated by lahars in tha past are superimposed on all valleys surrounding the volcano..
2.) The lahars that flows down rivers and stream valleys cause high risk of flooding .the lava may flow into various valleys .However evacuation can be aided with the help of lahar-warning system.
3) Since the distance from orting to mount rainier is 73 km,the average speed is 73/40=1.81km/minute.
The lahar speed will increase as it flows down the puyallup river valley as this valley is more susceptible to lahars caused by collapse of the flanks.
4) Distance between orting and pullayup is 12 km,so the time of travel will be 6 minutes.
5) Since lahars occur with no warning most of the time ,only best evacuation advice would be to help local people and educate them how to live more safely with the volcano.
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