1. Viscosity depends primarily on the composition of the magma, and temperature. Which of the following statement is correct? A. Higher SiO2 (silica) content magmas have low viscosity. B. Lower SiO2 (silica) content magmas have higher viscosity. C. Higher SiO2 (silica) content magmas have higher viscosity. D. There is no relationship between viscosity and silica content. 2. Types of volcanoes vary from quiet to explosive. Which of the following factors greatly affects the eruption of a volcano? A. altitude C. size B. shape D. temperature 3. When the pressure exceeds the strength of the overlying rocks, what usually occurs in the volcano? A. earthquake C. tsunami B. fracture D. None of these 4. Which of the following types of eruption is characterized by a periodic weak to violent eruption characterized by fountain lava? A. phreatic C. strombolian B. plinian D. vulcanian 5. You are a volcanologist from Bicol. On your way back to your hometown, you saw the eruption of Mayon Volcano characterized by a violent and excessive ejection of pyroclastic debris and other volcanic materials, which eruptive style is described in the scenario? A. phreatic C. strombolian B. plinian D. vulcanian
