Physical Geography

Folding, Faulting, Denudation

The Frank Slide

Introduction 

In 1903 a disastrous landslide took place at Frank, Alberta.  A huge slab of limestone slide from the face of Turtle Mountain and wiped out part of the town.  This activity has two parts.  In the first, you do a little reading about the slide and summarize what went on.  In the second part you do lab related to the topic.

  
http://sts.gsc.nrcan.gc.ca/page1/geoh/graph/frank2.jpg

Part 1.    Background reading and report

Consult the websites below, and any other sources you might come across, and prepare a one to two page report on the Frank slide.  Concentrate on the basics and don't get too distracted by the details of the human story.  Use the following as points to focus upon: http://www3.sympatico.ca/goweezer/canada/frank.htm
http://www.frankslide.com/boulder.html

Part 2 .    Frank Landslide Lab

This lab has been adapted from Physical Geography, 3rd edition, by Arthur N. Strahler, pp. 412-413.

You will need to consult the two images noted below to complete this lab.  You will have to print a copy of the map.  On the map the limit of the slide is shown by the dashed lines.  Note that the contour interval has been reduced on the east side of the river to show details of the relief in the slide area.  You will see that the units used are in feet and yards and not meters that you are likely used to.  Remember that there are 3 feet to a yard, 1760 yards to a mile and 5280 feet to a mile.  A yard is just a little short of a meter. A mile is about 1.6 km. (Aren't you glad you use meters most of the time?!)  The scale of this map is 1:9,600.  Assume that every one of the tick marks is 100 yards.  To determine location on the map, you need to use the grid numbers and marks on the west and south sides.  The first number in the pair is the easting, the second is the northing.  (You can remember this with "Read Right Up".)

You will need a ruler, protractor, and pencil to complete this lab.

Frank Slide Map
Frank Slide Block Diagram

1. (a)    What two contour intervals are used on the map?
    (b)    What is the length, in miles, of the landslide area, measured from South Peak (0.3-0.3) to 3.6-1.5?  You'll probably measure in cm so you'll have to convert.

2. (a)    What is the elevation of the unusual, hachured, contours at 2.4-1.2 and at 3.3-1.4?
    (b)    What is the summit of the elevation of the hill of landslide debris at 2.2-1.0?

3.    Assume that the volume of debris east of the Crow's Nest River to be 30 million cubic yards, what is the average thickness of the landslide debris within the limits of the slide on the east side of the river?  To do this, print out a copy of the map and draw in with a pencil the 100 yard grid.  Total the number of squares and part squares within the dashed lines. (You will be handing this map in so you MUST do this on your own).

4. You are now going to look at changes in elevation and distance between two specific contour lines on the map.
    Contour 1 is at 6000 ft (0.68 - 1.5) and contour 2 is at 5000 ft (0.96 - 1.5)

(a) Calculate the vertical difference in elevation between the two contours?
(b) Calculate the horizontal distance between the two contours.  (You will need to measure on the map and use the map scale)
(c) Given the information you calculated in a) and b) above, calculate the approximate distance if you were travelling down the slope (face) of  the mountain between the two contours.
(d)  What is the slope of the mountain. (the distance you travel for every 1ft change in elevation)
(e)  Draw a right triangle whose legs are scaled proportionally to the vertical and hortizontal distances obtained in (a).  Measure the angle of this triangle with a protractor and state the angle in degrees.

5.    Draw a cross-sectional profile from 0.0-0.4 to 3.8-1.5.  Use a vertical scale equal to the hortizontal scale of the map.  Label the relevant features.
 

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