Volcanoes and Volcanic Hazards - Investigations in Environmental Geology - page 56

FIGURE 4.2 Magma volumes from several different volcanic eruptions (from Fischer, Heiken, and Hulen, 1997).

however, that each of these eruptions produced major
pyroclastic flows that traveled far from their respective
volcanoes. All eruptions created major calderas.

3. Refer to Figure 4.3. Do you live in an area that has been
impacted in the past by tephra (ash) from either volcano?

4. From the ash distribution data, were the wind directions
the same for each eruption?

QUESTIONS 4, PART A1

1. How do the sizes of the larger Yellowstone and Long Val-
ley eruptions (Table 4.3) compare with eruptions shown in
Figure 4.2?

5. Figure 4.3 shows where tephra from Long Valley and Yel-
lowstone are found now. Do you think that the current distrib-
ution of tephra is an accurate map of the original distribution?
Explain.

2. Use the data on Figure 4.2 to help determine the approxi-
mate "Long-Term Recurrence Interval" and record your
result in Table 4.3.