Lab 2: Karst and hillslope processes and landforms 

a) Consider a 8 kg boulder sitting on a 14° slope. Determine whether the boulder will move by calculating the stability factor (F). Be careful of units! (3 pts)

b) Now consider the same slope is covered with a 3 m thick layer of loose material over a solid sliding plane. The water table is 0.7 times this thickness (𝜇) and laboratory analysis has shown that the material has a cohesion of 5 kN/m2, a unit specific weight of 12 kN/m3, and an angle of repose of 8°.  Assume that the specific weight of water is 9.8 kN/m3. Determine whether the boulder will move by calculating the stability factor (F). Be careful of units! (4 pts)

4) Hattian Bala Landslide, Pakistan (8 pts)

a) Fly to Hattian Bala stop and observe the most recent satellite imagery (2021). What evidence of a previous mass wasting event can you identify? (2 pts)

b) Use the historical imagery tool to compare the current landscape with the landscape in 2002, before the mass wasting event. Explain the formation of the Zalzal Lake. (2 pts)

c) Using the path tool, calculate the average slope of the landslide debris from the most recent satellite imagery (show all your work). (2 pts)

d) Fly to the Hattian Bala stop 2. Compare the imagery from 2002 and 2010 in this location. Describe the differences you see and explain why they occurred. (2 pts)

5) Oso Landslide, USA (22 pts)

a) Fly to the Oso Landslide stop. Using the time historical imagery tool, can you guess a timeframe of when the landslide(s) occurred? (1 pt) Note that there may be more than one that occurred since satellite imagery was available.

b) Confirm the exact date of the most recent (and largest) Oso Landslide by researching the event. On what exact date did this event occur? (1 pt)

c) Using the most recent satellite imagery following the slide and comparing it to imagery both before and after, describe the effects of the most recent slide on the Steelhead River both upstream and downstream. (2 pts)

d) Look at the forested area surrounding the slide over the years. Can you identify a human activity that may have contributed to the slide? (1 pts) Explain how this activity influences hillslope processes. (3 pts)

e) Historical weather data indicates that prior to the most recent slide, the Oso area had heavy rainfall during the previous 45 days that was 200% percent of normal. Explain how this may have contributed to the event. (3 pts)

f) A Seattle Times article published following the event included the following:

“John Pennington, Director of Snohomish County’s Department of Emergency Management, stated…, ‘This was a completely unforeseen slide. This came out of nowhere.’” (Armstrong, Carter & Baker, 2014)

From what you’ve seen in this lab and any additional research, do you agree with this statement or were there warning sign that such an event may occur in this area? Be sure to properly cite any outside sources. (4 pts)

g) Using the path tool, calculate the average slope of the landslide debris from the most recent satellite imagery. Show all your work. (2 pts) Explain why it may be different that of the Hattian Bala landslide. (2 pts)

h) Using figure from the Arizona Geological Survey (on the next page) and other information you have learned about the Oso Landslide, what type of mass wasting event would you classify this as? You can have more than one answer, as long as you justify it with your observations. (3 pts)

Extra resources to help you:

This interactive map by the Seattle Times shows the history of mass wasting events in the area.

This video, published by the US Geological Survey, shows the results of a simulation of the Oso Landslide. Observe how remarkably quickly the slide took place.