Question

Volcano A erupts rocks with SiO2 content ranging from 49% to 52% whereas volcano B, 100km away, erupts materials with SiO2 content of 62-68%. Which statement best characterizes these two volcanoes?
A. Both volcanos are shield type volcanos that are characterized by quiet eruptions.
B. Both volcanos are violent, explosive volcanos that spread ash continent wide.
C. Volcano A is likely to be a supervolcano with violent eruptions, whereas volcano B is probably a shield volcano with quiescent eruptions.
D. Volcano A is probably a shield volcano with typically quiescent eruptions,whereas Volcano B is likely a stratovolcano characterized by violent, explosive eruptions.

Answer 1

Answer:

Option B

Explanation:

Shield volcanoes are the ones which have low silica content in their lava and due to this reason the eruptions are violent and of high fluidity. On the other hand volcanoes that have lower silica content take time to rise to the surface of the volcano opening and also the eruptions are of lower fluidity. Generally, high silica lava squeezes out silently through the cracks and fissures in the Earth.  

In both the volcanoes A and B the silica content is high. Thus, option B is correct