Exam 5: Volcanoes and Volcanism

Provide evidence as to why warning signals are not always indicative of impending volcanic eruptions?

The three main types of volcanoes are:

The volcanic explosivity index (VEI) can be correlated with the number of deaths caused by an eruption.

Describe igneous activity at convergent plate boundaries.

The two most active volcanic zones are the ____________________ belt and the ____________________ belt.

Shield volcanoes are composed largely of lavas of ____________________ composition, they commonly have slopes that are ____________________, and their eruptions tend to be ____________________ in explosivity.

An eruption of a viscous, felsic magma is likely to form a lahar.

Discuss what volcanologists look for in trying to determine if a volcano is about to erupt.

The volcanic explosivity index (VEI) is intended to:

The dominant gas emitted from volcanoes is ____________________.

Completion When basalt lava is chilled rapidly in the water in an ocean or lake, it forms bulbous structures called ____________________.

What is the difference between an active volcano and a dormant volcano?

Which is the correct ranking (in descending order) of regions with the most active volcanoes and volcanic activity?      1. Circum-Pacific belt 2. Mid-oceanic ridges 3. Mediterranean belt 4. Isolated sites like the Hawaiian Islands

Which magma type usually erupts from fissures?

Cinder cones rarely reach heights greater than ____________________; they are composed of ____________________ material of ____________________ composition.

The chemical composition of all lavas is the same.

Why does most volcanism at spreading ridges go undetected?

A nuée ardente is composed of fiery hot gases and dust.

Describe shield volcanoes. What are they composed of? Where are they found?

Describe the volcanoes that form the Hawaiian Islands, especially on the island of Hawaii.