A. _Multiple Choice Questions 1. What is the term for the process by which magma rises to the surface due to a decrease in pressure? a) Decompression melting b) Magma differentiation c) Crustal thinning d) Volatile content increase 2. Which volcanic hazard is characterized by a fast-moving, hot cloud of ash, gas, and rock? a) Lahar b) Pyroclastic flow c) Volcanic ashfall d) Lava flow 3. What is the name of the theory that explains the formation of volcanic arcs? a) Plate Tectonics Theory b) Island Arc Theory c) Subduction Zone Theory d) Continental Drift Theory _ B. 1. Describe the differences between phreatomagmatic and phreatic eruptions. 2. Describe the process of volcanic island formation through seafloor spreading. 3. Explain the role of volatiles in magma dynamics. C. True or False 1. Volcanic ash can affect global climate patterns. 2. All volcanic eruptions produce lava flows. 3. The Pacific Ring of Fire is home to 75% of the world's active volcanoes. pakisagot po
Answer (1)
A. Multiple Choice Questions1.a2.b3.aB. Short Answer1. Describe the differences between phreatomagmatic and phreatic eruptions.Phreatomagmatic eruptions occur when magma interacts with water, creating explosive reactions due to the rapid vaporization of water. This type of eruption typically produces more ash and fragmented material.Phreatic eruptions involve the heating of groundwater by magma without the direct involvement of magma itself. These eruptions are driven by steam and typically do not produce new magma or lava.2. Describe the process of volcanic island formation through seafloor spreading.Volcanic islands can form through seafloor spreading when tectonic plates diverge. Magma rises from beneath the Earth's crust to fill the gap between plates, creating new oceanic crust. Over time, repeated volcanic activity in this spreading zone builds up enough material to form islands above sea level, such as those found in mid-ocean ridges.3. Explain the role of volatiles in magma dynamics.Volatiles, such as water vapor, carbon dioxide, and sulfur dioxide, play a crucial role in magma dynamics by lowering the melting point of rocks and increasing the explosivity of eruptions. The release of these gases can build pressure in magma chambers, contributing to violent volcanic eruptions when they are suddenly released.C. True or False1. Volcanic ash can affect global climate patterns.True – Large volcanic eruptions can release ash and sulfur dioxide into the atmosphere, reflecting sunlight and cooling global temperatures temporarily.2. All volcanic eruptions produce lava flows.False – Some eruptions, like explosive pyroclastic eruptions, may produce ash, gases, and pyroclastic flows without lava flows.3. The Pacific Ring of Fire is home to 75% of the world's active volcanoes.True – The Ring of Fire is a major area in the Pacific Ocean basin known for frequent earthquakes and a large number of active volcanoes.
