Lab Exercise 7

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.