Lab03 - Instructions

Geography 208 Lab 3: Analysis of Mass Movement Processes Due: Week 10 (Nov 13) before your lab session INSTRUCTIONS on FORMAT and SUBMISSION:  Each individual must submit their own report, written in their own words.  Create your own Lab Report this week (there is no “Report Template”). Follow the general style of previous reports. Please present your work in a clear and logical fashion.  Submit in OnQ under “Assessments” > “Assignments” > “Lab 03” as a Word or PDF. We will not accept photos or HEIC file types. Assignments submitted as this type will be marked late until it is resubmitted as a Word or PDF document.  Each figure and table you include needs to have a caption that clearly describes what is shown in the figure or table . Note a figure/table caption is more than a figure title! A properly formulated figure caption would describe the data/information presented so that the reader can understand the results, and derive their own meaning from this, without having to read or refer to the accompanying text.  Note that this course makes use of Turnitin, a third-party application that helps maintain standards of excellence in academic integrity. When you submit your assignments through OnQ, your assignment will be subject to a scan by Turnitin, for the purpose of detecting plagiarism. You will be given a similarity score and will be able to view this. You will also have the opportunity to revise and resubmit if you find that you have a high similarity score. PART 1: You are required to share the airphoto images and maps. Therefore, you will have to work in groups of two. Stereoscopes, copies of the aerial photographs, and map sheets will be provided Stereoscopes and copies of the photos and maps are only available during the scheduled lab times, therefore you must come to lab to do this part of the assignment. Please do not mark or write on photographs or maps. Where calculations are required show the steps involved for full marks. PART 2: You will require the use of the Google Earth (desktop version) (desktop version, available free at https://www.google.com/earth/versions/). You can work on Google Earth exercises in your own time. You should not need to cite sources beyond the text book, lectures or assigned readings. However , if you do make use of other resources you need to provide a proper in text citation (e.g. Author, YEAR) and a full reference in a separate reference list at the end of your report. Failure to cite source of information or knowledge is plagiarism, which is a breach of academic integrity . You may choose any referencing format, but must use it consistently. See examples from Lab 02.

GPHY 208 Lab 3 2 / 7 Introduction: Although mass wasting processes can be classified simply as slides, flows, falls, etc., in reality many slope movements or failures are complex and may involve several styles of movement. Similarly, the reason for failure or movement may be complex and involve several of the individual factors described in lecture (e.g. pre-existing failure planes, removal of lateral support, addition of water, alteration and remoulding of the constituent material, etc.). PART 1: Mass movements in the Ottawa Valley Background : The South Nation River crosses the flat floor of what was once the C hamplain Sea about 40 km southeast of Ottawa. Along its course, and in tributaries and other creeks nearby, one sees evidence of a history of past retrogressive (back-cutting) failures. The particular failure shown in the accompanying stereo-triplet (air photo) occurred on May 16, 1971, along a large river meander bend approximately 6.5 km north of Casselman, Ontario. Here, the overburden strata consist of i. 4 m thick layer of medium sand, which is underlain by a ii. 3.5 m of stiff clay, followed by iii. 6.5 m of soft to very soft clay and silty clay, iv. 10.5 m of medium stiff silt, (v) 4.5 m of stiff silty sand, and finally v. 10 m of dense till that rests on bedrock. The mass movement had the effect of breaking hedgerows crossing agricultural fields (dark lines in the photo) into segments and carrying them downstream across the failure bowl. Part 1 Assignment (29 marks total): 1. Using graph paper (provided on OnQ site as “Lab 03 – Strat Grid”) construct a simple stratigraphic column showing the sedimentological units described in the background information above . Note: A stratigraphic column has height/depth of the sedimentological unit on the y-axis , and particle size on the x-axis. Your column should include axes labels, a title, and other annotations as necessary . (8 marks) . Hint: this will look somewhat like a sideways bar chart depicting the sediment grain size and for what depths. 2. Examine the stereo-triplet in OnQ depicting the 1971 landslide (“Lab03 – AirPhoto Triplet.jpeg”). Within the recently failed area, dark grey tones denote remnants of the former upland surface that have subsided and shifted, while pale grey tones denote exposed sub-surface material . Examine the former surface within the failed area, and the trajectory of hedgerows indicated at 1 & 2 that are spread across the failed area to 3 & 4. What do the shape and dimensions of the failed area (e.g. shape of the failed area, scarp, and length to width ratios), the topography of the disturbed surface, and path (trajectory) of the hedgerows (which were straight lines before the slide) tell you about the type of movement (i.e. flow, heave, sliding, spreading, and/or slumping)? (4 marks) a. Identify and justify the type of mass movement that occurred closer to the main scarp. (2 marks) b. Identify and justify the type of mass movement that occurred closer to the end point reached by the event. (2 marks) 3. Find Casselman, Ontario using Google Earth, and locate the site shown in the air photo.

GPHY 208 Lab 3 4 / 7 Figure 1 Block Diagram of Frank Slide Part 2 Assignment (21 marks total): 6. Refer to the topographic map of the Frank Slide area (Figure 2). The dashed lines on both the map and block diagram delimit the area of the failure and accumulation of debris. The marginal scale is in 1000's of feet (further sub-divided into 100's of feet ). Notice that a more detailed contour interval is used within the area of slide debris east of the Crow's Nest River to better show its morphology. What are the two contour intervals used on the map? (2 marks) 7. Find the slide on Google Earth. (a) Using the Google Earth tools. Calculate a ratio of the maximum length (from the peak to end of the debris field) to width for the slide (i.e. average width within the zone of failure, not the width of the accumulation zone or debris field). Present the ratio as X:1. Discuss how your finding for the Frank Slide length to width ratio compares to typical values for slides (e.g. see your text book or lecture notes). (2 marks) (b) Using the tools in Google Earth. Find the area of the zone of accumulation. Explain your methods and provide a map of the area you have calculated. (3 marks). (c) A classmate is of the opinion that this debris field is the result of a flow that must have involved abundant water. Provide a geomorphologically based rebuttal of this opinion. In other words, explain the evidence you see in the shape, size, distribution, microtopography,

GPHY 208 Lab 3 5 / 7 etc.. of this failure that supports that this would have been a dry debris avalanche rather than a wet debris flow . (4 marks) (d) Assuming the average thickness of the debris field is 12 m , calculate the volume of the debris accumulated in m 3 based on the dimensions of zone of accumulation calculated in 7b (1 mark). Discuss how this volume you have estimated compares to the published estimate of 33 million m 3 of material that was moved in this event? (i.e. is your estimate greater/less? By how much? What might explain the difference?) (2 marks) 8. Examine the area and slope of the mountain near the Frank Slide (a) Using the path function in Google Earth calculate the slope (vertical height (d v )/horizontal distance (d h )) of Turtle Mountain (note this is after the slide) from the peak of the mountain to the valley bottom (give your answers in m/m). Show your calculations for finding slope and your values for d v and d h . ( 3 marks) b) Given that the peak elevation was approximately 2450 m prior to the event (and valley floor elevation at 1250 m, and 1.55 km horizontal distance from the peak) calculate the normal force and the shear force of a boulder approximately 4m by 3m by 8m on the top of the slope prior to the event. Assume that the density of the boulder was 2400 kg/m 3 . Use the vertical (d v ) and horizontal distance (d h ) from the peak to the valley floor (as shown in the conceptual diagram) to calculate the hypotenuse and the value of cos and sin. Please show: d v , d h , the slope hypotenuse, the boulder mass, the normal force and shear force. (5 marks) Part 2 Total: _____/ 21 m = mass d v = vertical distance d h = horizontal distance  = slope angle g = acceleration due to gravity _______ hypotenuse =  (d h 2 +d v 2 ) d v  d h

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