Exam 6: Volcanoes Tectonic Environments and Eruptions

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.

When comparing the characteristics of common magmas or lavas, ____.

The two most abundant gasses in magmas are ____. ​

Rift zones where a volcano spreads in different wedge-shaped sections are characteristic of ____.

Most volcanic ash consists of curved shards of glass.

The viscosity of different types of magma is controlled by the peridotite content.

A low, bowl-shaped crater encircled by a low rim is a(n) ____.

The magma that erupts from the divergent boundary of the Mid-Atlantic ridge produces ____.

Basaltic magma generally produces non-explosive eruptions.

Stratovolcanoes have relatively steep sides because ____.