bree_hernandez_lab_15
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Metropolitan Community College, Kansas City *
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101
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Geography
Date
Dec 6, 2023
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Uploaded by ColonelStarKookabura14
Mass Wasting (Lab 15)
For this lab you will need the following:
●
Google Earth
●
Mass Wasting KMZ file (posted in lab 15 assignment link in Canvas)
Location 1: Mt. St. Helens
●
Click the link for the “Mass Wasting” KMZ file to begin this activity.
●
Open the “Location 1: Mt. St. Helens Lahar” folder and click the icon for the “Mt. St. Helens
Lahars” placemark to fly to it. Open the placemark balloon. Click through to the lahar images
linked there.
●
Click and fly to the icon for placemark A, and open placemark A’s balloon. The image is of the
Toutle River valley lahar, taken 24 years after the eruption.
●
Click and fly to the icon for placemark B, and view the close-up image of the lahar in that
placemark.
●
Click and fly to the icon for placemark C and click through to the web page detailing efforts to
control sediment flow in the downstream reaches of the Toutle River.
1.
Describe the man-made structure at placemark C, and explain how it works and why it was built.
It is a dam and it's meant to hold back water in order to control flooding, generate energy, or store water.
●
Use the Search panel to fly to Orting, Washington.
2.
Notice that Orting is located at the confluence of two rivers. The river NE of town is the Carbon River,
the river to the SW is the Puyallup River. Trace both of those rivers upstream, and describe the location
and source of water for those streams.
They both originate from Mt. Rainier.
3.
What hazards would the inhabitants of Orting face in the event of an eruption of Mt. Rainier (25 miles
SE of Orting), and what plans can be made or actions can be taken to prevent loss of life and property if
an eruption occurs?
A polluted river, smoke, and volcanic ash and sediment would all pose a threat. A sediment retention
structure, such as the one seen in the Tootle River, might be an option to keep the material from
reaching them.
4.
Search for Carbonado, Washington, and explain why the inhabitants of Carbonado, though closer to
Mt. Rainier, are in less immediate danger of inundation by a lahar if Mt. Rainier were to erupt.
The inhabitants of Carbonado, Washington are less in immediate danger from lahar due to eruption of
Mt. Rainier because they are protected by their location and the surrounding vegetation, which creates
friction and reduces the speed of a lahar. The inhabitants can also easily evacuate as they are near roads
and highways.
5.
Compare the appearance of the Puyallup and Carbon River valleys around Orting with the Toutle River
valley at placemark A. How are the valleys similar? And how are the valleys different?
All three rivers appear to be braided, but the Toutle appears to have cut out a broader valley as a result
of the water's cutting action.
6.
Describe any evidence you see that suggests the Puyallup and Carbon River valleys have been the sites
of lahars in the past.
Lahar flow has previously occurred in the Puyallup and Carbon River valleys. They're in a good location
due to the fact that the river receives water from a neighboring glacier.
Location 2: La Conchita, California
●
Open the “Location 2: Coastal California” folder and click the icon for the “Location 2: La
Conchita Landslide” placemark to fly to it, and open the placemark balloon. Click through to
view the video (works best in Internet Explorer) and read the description of the January, 2005
event.
1.
What geologic conditions existed in the area prior to the 2005 slide that pre-disposed the area to
future slides?
The houses were all built at the base of a steep slope that had already experienced a slide prior. Experts
had also declared it was a recurring slide.
2.
What were the immediate causes of the 2005 slide?
The landslide occurred after a 15-day period of unprecedented records of rainfall in Southern California.
Seasonal rainfall had been constant in the area, triggering a slope failure.
3.
Determine the gradient between placemarks A and B (on the slide itself) and between placemarks C
and D on the intact slope adjacent to the slide.
Gradient on the slide = __
35%_____ Gradient on the intact slope = ___
50%_____
4.
Describe how the occurrence of the slide helps to stabilize the material that has failed during the slide.
How the occurrence of the slide helps to stabilize the material that has failed during the slide because
the failed material will continue to move until it comes to a complete stop at a stable spot.
Location 3: La Jolla, California
●
Open the “Location 3: La Jolla Landslide” folder and click the icon for the “Location 3: La Jolla
Landslide” placemark to fly to it, and open the placemark balloon. Click through to the slide
show.
●
Click on the “Soledad Mt. Road Map” overlay in the Places panel, and set the opacity slider to
about 25%. Then fly around the area to familiarize yourself with the level of development and
the topography of the land. Turn on the “Roads” layer in the Layers side panel.
1.
Find two or three other areas (within 0.75 miles of the Location 3 placemark), and list the names of
the streets in the area that you think might be subject to damage by landslide in the future. For each
location you cite, describe why you think the area is vulnerable.
Regions like the Appalachian Mountains, the Rocky Mountains and the Pacific Coastal Ranges have
"severe landslide problems," according to the USGS. The Three location that might be subject to damage
by landslide in the future such as, Oregon, Alaska and Hawaii as especially prone.
2.
Compare the La Conchita event with the La Jolla slide with regard to a) pre-slide warning signs, b) the
future threat to property and human life, c) the speed at which the events occurred, and d) the geologic
setting of the slides.
La Conchita event killed 10 people and La Jolla killed 8. La Conchita occurred a second time 50 years
later. Both the landslide la Conchita and la Jolla occurred in a sudden situation, la Conchita occurred due
to the immense rainfall and the la Jolla landslide happened due to the slipped loose earth materials on
the side of Mount Soledad, which destroyed eight luxury houses. A previous landslide occurred in both
places which gave an indication such as crown crack. As well as the landslide in La Conchita was formed
due to the highly saturated content of water which overlies on Precambrian rock. Cracks or unusual
bulges in the grounds of la Jolla. Severe storms, earthquakes, volcanic activity, coastal wave attacks, and
wildfires are future threats of these landslides. Both landslides occurred in a sudden event after the
indication. The area is covered with tertiary sediments and underlined with Archean crystalline rocks
geologically. The sedimentary sediments easily get saturated and fail into a landslide.
3.
What actions might local governments in each community take to ameliorate the effects of future
events, or to eliminate a recurrence entirely?
To ameliorate the effects of future events and their possible elimination, the government must have the
necessary preparation to overcome the existing issue or totally eliminate it. Additionally, it must have
professionals scope related to the landscape.
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