Exam 6: Volcanoes and Mountains

Use the graph below to answer this question. One point represents basalt, one andesite and one rhyolite. -Which point on the graph is most likely to form andesite?

What type of volcano is Mount St. Helens and what caused the explosion?

Magma and lava are the same expect one remains below the surface and the other erupts on the surface.

Crater Lake in California formed in one of these.

Mountains are generally extinct volcanoes.

High viscosity lava flows faster than low viscosity lava.

How much do mountains rise with each addition of 1000 meters of crustal material?

Mountains have crustal roots that help support them.

What evidence indicated that Mount St. Helens was going to erupt?

Where are most volcanoes located?

Scientists were able to predict the May 18^th, 1980, eruption at Mount St. Helens.

Use the Venn diagram below for this question. -Hawaii is an example of this type feature.

Which type of magma formed the Hawaiian Islands?

Why were there casualties associated with the Mount St. Helens eruption of 1980?

Use the graph below to answer this question. One point represents basalt, one andesite and one rhyolite. -Which point on the graph is most likely to form basalt?

Use the following map to answer this question. -Identify a volcano that is most likely to have both basalt and rhyolite as products of its eruption.

The following excerpt is from: Ewert and Miller, June 1995, The USGS/OFDA Volcano Disaster Assistance Program: USGS Open-File Report 95-553. Use the excerpt to answer this question. The strategy employed by the Volcano Disaster Assistance Program (VDAP) is to reduce loss of life and minimize economic disruption. It includes instrumental monitoring to detect the movement of magma (molten rock) toward the surface and thereby forecast eruptions and assessments of volcano hazards and risk based on past eruptive events at a volcano. A great majority of the world's potentially active volcanoes are unmonitored. Less than twenty-five percent of volcanoes that are known to have had eruptions in historical time are monitored at all, and, of these, only about two dozen are thoroughly monitored. Moreover, seventy-five percent of the largest explosive eruptions since 1800 occurred at volcanoes that had no previous historical eruptions (Simkin and Siebert, 1994). Thus, until regular volcano surveillance is much more widespread, a mobile crisis-response capability is needed to quickly assess hazards and install monitoring equipment when a volcano becomes restless. VDAP sends groups of scientists to active volcanoes about to erupt that also pose a threat to humans. -Which one of the magma types listed below is of least interest to VDAP?

Use the Venn diagram below for this question. -Which feature(s) are present at plate boundaries?

Why were trees knocked down for tens of kilometers north of Mount St. Helens?

What happens to a mountain root as erosion removes material from the summit?