Author Question: Subduction zones are common sources of volcanoes. Explain the key details of the process of volcano ... (Read 41 times)

Beheh · **on:** Jul 13, 2018

Subduction zones are common sources of volcanoes. Explain the key details of the process of volcano formation along subduction zones.
What will be an ideal response?

Question 2

Montserrat, an island on the edge of the Caribbean plate and South American plate, is dominated by the Soufriere Hills volcano. The volcano is moderate-sized with moderately steep slopes. Beginning in July of 1995, the volcano began erupting in a style associated with magma contacting surface water. The magma vent hardened in a rounded shape out of rock containing a mix of rhyolite and basalt, stopping the eruption after 18 weeks. The collapse of one side of the dome sent ash and mud streaming down over the capital city and main airport, rendering them uninhabitable.
Describe the events above using as many terms from the chapter as possible.
What will be an ideal response?

Galvarado142 · **Reply #1 on:** Jul 13, 2018

Answer to Question 1

ANSWER: The subducting oceanic plate has a high water content. This water boils off as it descends and rises under the peridotite supporting the continental plate above. The water allows the magma to melt at a lower temperature. The peridotite melts to form basaltic magma, which is less dense than its surroundings and begins to rise. The rising basaltic magma can melt granitic rock to form rhyolite. Either the rhyolite, basalt, or intermediate andesite magma melts through to the surface to form a volcano.

Answer to Question 2

ANSWER: The Soufriere Hills volcano is an andesite stratovolcano formed at a subduction zone. The 1995 event was a phreatic eruption, stopped by the formation of a lava dome in the volcano vent. The collapse of one side of the zone created pyroclastic flows and lahar, damaging the capital city and airport.