The Following Excerpt Is From: Ewert and Miller, June 1995

Multiple Choice

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 volcanoes are most likely to explode and why?

A) Strato- because the magma is more viscous than in shield volcanoes
B) Strato- because the magma is less viscous than in shield volcanoes
C) Shield- because the magma is less viscous than in strato-volcanoes
D) Shield- because the magma is more viscous than in strato-volcanoes