Geomorphology Project Instructions F2023
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School
Brigham Young University *
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Course
110
Subject
Geography
Date
Dec 6, 2023
Type
docx
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4
Uploaded by scrimpss
Geomorphology and Hazards Project
Geography 110: Landscapes of Disaster
Overview:
For this project, you will be using Google Earth or Google Maps to observe and describe a number of areas that are prone to geological hazards. The main purpose of this exercise is to help you observe features produced by some of the hazards we’ve talked about recently (the study of these features is known as geomorphology). Navigating:
To get to a specific geographic location, just copy and paste the latitude and longitude coordinates given for each site to the search bar. In Google Earth
, you will have a set of navigating controls in the upper right-hand corner, and along the bottom of the screen you have a
scale bar, the latitude and longitude, the elevation of the land the cursor is directly over, and the “eye altitude,” or elevation from which you’re viewing the landscape. You can also right-click and drag your mouse to zoom in and out and rotate your view. In Google Maps
, you can switch between map-view and earth-view in the bottom left-hand corner, and use control + mouse click-
and-drag to zoom and rotate your view. Historic Earthquake Faults kmz File: Under the same link as these instructions on Learning Suite I have posted a .kmz file, which shows faults where earthquakes have occurred in historic times (i.e. within the last 100 years or so). If you are using Google Earth for the project, download this file and then double-
click on it. Google Earth will open (if it isn’t already) and automatically zoom out to a view from
which you will be able to see all of the faults contained in the file. You will then need to copy and paste the coordinates for site 4 below to answer those questions.
Let’s get started: Go to each of the sites below by copying and pasting the coordinates into Google Maps or Google Earth and spend some time panning and zooming around the broader landscape and then zoom in closer on any areas of interest. Scroll around, go to an oblique view and try to get a good feel for what’s going on there. Answer each question for each site, and then record some of your own observations and reactions in the space provided. For the observation/reaction portions,
the following questions should help to get you thinking:
Look for evidence of previous disasters in the area. What are the “fingerprints” of different hazards on the landscape?
Pay specific attention to man-made structures, and nearby cities and towns. Which of these is/are at the greatest risk?
How have people responded to these hazards? Do they seem to recognize that they are there? Can you see anything that has been done to make things safer? What else could be done?
Would you build your home near this site? Why or why not? If yes, where?
(You do not have to address all of these with your observations, but they will get you started)
SITE 1 – Lake San Cristobal: 37 59 19.86 N, 107 15 58.37 W a)
How was the lake (Lake San Cristobal) created? Which direction, then, is the river is flowing – north-to-south or south-to-north? What were some likely effects of this event downstream and upstream from where it took place? The lake was created when a portion of the nearby mountain, Mesa Seco, to slump leading to an earthflow and creating a natural dam. The river flows north to south. Some likely effects include the damming of the flowing river which would lead to sediment build up, impacts on the vegetation in the area, and potentially make areas upstream more unstable and vulnerable to additional landslides. b)
Focusing especially on and around the landslide itself, what are some natural and human changes/developments that have taken place since the last event occurred?
One of the most notable human changes is that several roads have been built around and through the flow. A natural change is that as parts of the flow continue the surrounding trees are uprooted and scattered. Observations/Reactions:
There are several man-made structures nearby including a scenic overlook and a campground. It would be hard to miss this earthflow, but I wonder if tourists especially recognize that there are still parts of it that are active. Overall, it seems like a reasonably safe place for humans because the flow is so slow, I did a little research as well and many geologists predict it will eventually stop. SITE 2 - Mt Vesuvius: 40 49 15.60 N, 14 25 33.66 E a)
Do you see any evidence that this volcano has erupted before? In which direction do you think the impact was the worst? Explain. (Changing to an oblique view and rotating around the volcano will help).
Yes, you can see evidence of lava flows. The flow looks to start at the base of the volcano, flow North, and then flow West so I would think the impact was the worst in areas located West of the eruption. b)
What impacts might another eruption have on the surrounding cities today (e.g. Pompeii)? How might they be different than in 79 A.D.? Explain. There are still many cities surrounding the volcano so I would think similar impacts would occur should another eruption occur including lava flows that could destroy settlements and ash and pumice would pollute the air. I think these would be less destructive to human life than in 79 A.D. as geology has come much further and we have a better understanding of hazards and strategies to lessen the damage such as prediction of eruptions and evacuation plans.
Observations/Reactions
: I thought it was interesting just how many cities surround Mt. Vesuvius and how close they are considering how devastating the eruptions have been. I would think areas such as Massa di Somma and Vesuviuslandia are at the greatest risk as they are near the previous lava flows. The proximity of the volcano to the gulf of Naples also creates some concern should another eruption occur, it could lead to additional hazards such as tsunamis. SITE 3 – Mt. Rainier: 46 51 10.4 N, 121 45 30.25 W
a)
Describe some of the physical differences between Mt. Rainier and Mt. Vesuvius. Do
the areas surrounding these volcanoes face different types of hazards? Explain.
A notable difference between Mt. Rainier and Mt. Vesuvius is that Rainier consists of several glaciers and snow fields. The areas surrounding Mt. Rainier are much more likely to face hazards
such as an avalanche, erosion from glaciers, and hazards from runoff.
b)
Change to an oblique view and scan to the west and northwest of the volcano, and notice the river channels that extend out in these directions. If this volcano erupts, what will likely fill these river channels? Choose one of these channels and follow it until you come to labeled towns or cities and list their names here. Do these cities appear to be safe or
not? Why?
I followed the river channel that leads to the Puyallup river. The first few labeled towns this channel passes through are Electron, Graham, and Orting. The rivers will most likely be filled with volcanic debris and overflow with ice melt from the heat of the eruption leading to potentially catastrophic mudflows/lahars. In the event of an eruption, I don’t think these cities are
safe due to their proximity to the Puyallup river and its various river channels, there would likely
be a lot of damage from lahars. Observations/Reactions
:
I didn’t realize how many glaciers and rivers extend from Mt. Rainier. If you look closely, you can see some evidence of past activity such as lava flows near Little Tahoma Peak on the northeast side. There are also several areas with what looks to be displaced snow from previous avalanches. SITE 4 – Lost River Fault: 44 07 54 N, 113 50 20 W a)
If using Google Earth, notice the red line indicating a historically active fault at this site (if you don’t see it, make sure you have the historic.kmz file checked in the sidebar). If using Google maps, note that the thin white line directly under the pin drop and running north-south is a fault. Provide two pieces of evidence that this fault has been active recently.
Scanning along the fault, zooming in and out, and again using an oblique view should help. When zooming in you can see some debris and clay-like rock around the fault which is typically formed during fault activity. You can also see some additional ruptures that intersect with the main fault suggesting several instances of activity.
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b)
Notice that there is a highway (93) running along the west side of the mountains. Center your view over this highway at about 20,000 feet and follow it to the south for several miles, making observations along the way. Name one or two towns that might be affected by a future earthquake. What specific earthquake-related hazards are these towns likely to face? Explain.
The towns of Dickey, Chilly, and Mackay are all fairly close to the fault and highway. These towns would likely face hazards such as ground ruptures and shaking. You can also see a nearby body of water, Mackay reservoir, as well as several plots of field that are likely maintained with an irrigation system. This water could mix with sediment displaced from the shaking and create conditions suitable for liquefaction to occur. Observations/Reactions:
North of the pin is the Earthquake Interpretive Site which does suggest nearby residents and visitors are aware of the hazards. All the surrounding towns like to be very small and not very populated rural areas. I can’t see any measures that have been taken to create infrastructure to mitigate the damage an earthquake would cause in this area other than the educational site interpretive site.