What type of volcano is Mount St. Helens and what caused the explosion?
A. It is a stratovolcano that exploded when trapped gasses were quickly released.
B. It is a shield volcano that exploded when trapped gasses were slowly released.
C. It is a stratovolcano that exploded when trapped gasses were slowly released.
D. It is a shield volcano that exploded when trapped gasses were quickly released.
Answer: A
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What evidence shown on the map and stereogram suggests that the material in the deposit does not consist of coherent bedrock? (Hint: Contrast the appearance of the deposit with that of the surrounding mountain front.)
The following questions are based on Map T-26a, a section of the USGS “Spring Hill, Idaho,” quadrangle (scale 1:24,000; contour interval 20 feet), and Figure 38-9, a stereogram of the same region. The map and stereogram show a large mass wasting deposit at the foot of the Pahsimeroi Mountains in Idaho (44°17'39"N, 113°43'02"W).
A/an ________ is a break in the geologic record resulting from erosion or nondeposition or both. Fill in the blank(s) with the appropriate word(s)
What happens when dissolution occurs between halite and water?
A) Halite crystals break into sodium and calcium ions, which exist invisibly between water molecules. B) Halite crystals disappear and only water molecules end up being present. C) Water molecules break into hydrogen and oxygen ions, which exist invisibly between halite crystals. D) Water molecules disappear and only halite crystals end up being present.
Rhyolite magma usually erupts in which form?
a. ?thin, fast lava flows b. ?thick, fast lava flows c. ?thick, slow lava flows d. ?fast ash flows e. ?fine ash columns