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Physical Geology Helpful Lab Hints
Exercise 7: Aerial Photos
Problem 2
- a. Follow the instructions,
look at both figures. Look for the mountain shape and/or caldera shape
on Fig. 7.17 (you may not see both for each volcanic center). Look at
the color on Fig. 7.18 (the older centers may show little if any, of the dark
color associated with more recently active areas.
- b. My hint: the oldest
center shows the least evidence of lava activity.
- c. Which flows are the
freshest? The black ones on top, or the bluish-black ones on the
southeast side.
- d. Use the elevation scale
on the side as the horizontal scale as well.
- Slope is rise/run OR change in
elevation/distance
- For this exercise, it is best to express the
change in elevation in feet and the distance in miles. The slope is then
expressed in feet/mile.
- e. Measuring the length:
- To develop a scale, measure the distance
between UTM lines with a metric ruler and then simplify.
- Create a verbal scale.
- Remember: scale is expressed as
"distance on map" = "distance outside"
- Use metric units (cm & km)
- Simplify to 1cm = ___ km
- For example: if the distance is 5 cm, then 5
cm = 100 km which simplifies to 1 cm = 20 km.
- Now measure the length of the lava flow with
the ruler in cm and convert to km.
- For example, if the distance is 3.5 cm on the
photo, using the scale above, the distance would be 3.5 cm * 20 km/1 cm = 70
km.
- NOTE: The scale developed as
an example IS NOT the correct scale for this exercise.
Back to lab 7 help.
copyright © 2007 Mike Phillips (includes all
photos)
last updated: 09/13/07