recitation7 - GEOL 0820 Spring 2011 Recitation#7 Landslides...

Info iconThis preview shows pages 1–4. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: GEOL 0820 Spring 2011 Recitation #7: Landslides You will need a RULER to complete this activity!!! Name: _______________________________________ Recitation Time/Day: _____________ Read the attached “Landslide in Western Pennsylvania” handout before coming to recitation. I. Point Fermin, California (Figure 1) Beginning January 1929, an 800 m (½ mile) long slide, began sliding slowly seaward down the inclined bedding on top of a slippery clay layer. Movement was apparently triggered by excess water from yard irrigation seeping down through layers of weak clay, which expanded and lost strength. Movement continued until June 1930. No one was killed by this slow movement, but homes sitting atop the high sea cliffs were twisted out of shape and had to be removed (Abbott, 2009). Examine Figure 1 (next page) , which is an oblique air photo of the slide feature on the coast at Point Fermin. Answer the following questions in complete sentences. 1. Using the information in the handout, examine Figure 1. Do you think the Point Fermin slide is a: slump, earthflow, debris slide, or rockfall? Explain why. (5 pts) 2. Locate the main scarp and two minor scarps on the figure – draw lines indicating the position of these. (4 pts) 3. Does the slump appear to be stable over time? Why or why not? (5 pts) 4. From the “Landslides in Western Pennsylvania” handout, name 3 processes that may increase the landslide susceptibility of a region like Point Fermin. (3 pts) i) ii) iii) 1 GEOL 0820 Spring 2011 Figure 1 : Oblique air-photo of a rotational mass movement along the coast at Point Fermin, Palos Verdes Peninsula, California (from Judson et al., 2000). 2 GEOL 0820 Spring 2011 II: Madison Canyon, Montana (Figures 2 – 4) On August 17, 1959 a magnitude 7.5 earthquake (the largest earthquake ever recorded in Montana) triggered a large and fast-moving debris slide along the Madison River, at West Yellowstone, Montana. The slide involved about 28 million m 3 of rock, and traveled at a velocity of greater than 100 km per hour (60 mph). The slide dammed the Madison River, creating a lake over 9.5 km (6 miles) long and 60 m (200 feet) deep (Judson et al., 2000). Figure 2: Debris slide at Madison Canyon, Montana (US Geological Survey). You will be given Figures 3 and 4 at the start of the recitation. 1) Put arrows on Figures 2 and 3 to indicate the direction of the slide. (3 pts) 2) Using the elevation values associated with the post-slide topography shown on Figure 3, plot the post-slide topography on the cross section (Figure 4): Y-axis = elevation, X-axis = distance). Use a ruler and the given scale to estimate the distances between contour lines. (NEATNESS COUNTS!) (20 pts total) 3) From the cross section shown in Figure 4, what is the greatest thickness (in feet) of landslide debris removed from the mountainside south of the Madison River? (5 pts) 4) From the cross section shown in Figure 4, what is the greatest thickness (in feet) of landslide debris accumulated on the north side of the Madison River? Mark the location of the greatest thickness on your cross section. (5 pts) 3 Although the earth is a relatively hospitable...
View Full Document

This note was uploaded on 01/05/2012 for the course ASTRON 0089 taught by Professor Johnstein during the Spring '07 term at Pittsburgh.

Page1 / 5

recitation7 - GEOL 0820 Spring 2011 Recitation#7 Landslides...

This preview shows document pages 1 - 4. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online