Physical geography lab exercise 35. Question 1 & 2 Name Section EXERCISE 35 PROB
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Physical geography lab exercise 35.
Question 1 & 2
Name Section EXERCISE 35 PROBLEMS-PART III The following questions are based on Map T-2, the "Umnak, Alaska," topographic map (scale 1:250,000; okmok volcano before the caldera was formed. (You may also determine the elevation changes and distances needed to make these calculations by using Google Earth.) contour interval 200 feet). In this problem, you will estimate the height of the original Gradients can be used to estimate an elevation increase over a given distance. (See Exercise 34 for a review of gradients.) For example, if a mountain has a gradient of 1000 feet per mile, we can estimate that over a horizontal distance of five miles, the elevation will increase by 5000 feet. 5 miles X 1000 ft/mi 5000 foot elevation increase over five miles 1. Compute the gradient of the outer base of the Okmok Caldera along line EF. Use the coastline closest to Point E as the starting point for measuring horizontal distance, and the northwest rim of the caldera as the stopping point. It may be easiest to use the graphic map scale to measure out a distance of four or five miles, and then determine the elevation change over that distance. feet Elevation Change Gradient feet/mile 2. Estimate the height of the original volcano. Assume that the present gradient of the Okmok Caldera (calculated in problem 1) is the same as that of the volcano before it collapsed Given the complex history of the Okmok Caldera, this is a very simplistic assumption, but it can be used to provide a crude estimate of the volcano's previous height. Following line EF, what is the horizontal distance from the coastline (closest to Point E) to the center of the caldera? Multiply the horizontal distance (from problem 2a) by the gradient of the present caldera (problem 1). This is an estimate of the original elevation of the volcano before its collapse Approximately how much higher was the original volcano than the present caldera rim? (a) miles (b) eet (c) feet EXERCISE 35 PROBLEMS-PART IV-GOOGLE EARTHTM Go to the Hess Physical Geography Laboratory Manual, 12th edition, website at www .MasteringGeography.com and open the KMZ file for Exercise 35 Part IV, or scan the QR (Quick Response) code for this exercise to view the "Exercise 35 Part IV Google EarthTM video the meas as in PartII, estimate the original height of Mount Mazama before it collapsed to form the Crater Lake caldera (Chis will provide only a crude estimate of the height of the original volcano) I. Gradient of southern slope of Crater Lake caldera: 2. Approximately how much higher was Mount Mazama urement and elevation functions in Google EarthTM and the same calculation procedures feet/mile than the present caldera rim? feet 246Explanation / Answer
1. Solution, Elevation change E-F = (300-60)= 240 ft; horizontal distance = 15 mile The gradient is about = 240 / 15 = 16 ft / mile. Means gradient is 16 ft per mile. 2 a. The distance of Point E to the center of calarda is 7.5 mile. 2 b. 7.5 mile × 16 = 120 (original elevation of volcano before it collapse. 2 c. Present elevation minus before collapse elevation (247-120)= 127 ft.