GEO 101 Lecture Notes - Lecture 6: Convergent Boundary, Stratovolcano, Tuff
2 May 2017
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Chapter 5: volcanic eruptions: the year without summer. June 6-7th, 1816- 6 inches of snow in new york. Price of food increased sharply: 1815 eruption of mount tambora (indonesia) 4000 feet of mountain was removed by eruption. Rock and ash flew into the atmosphere. Toxic gases also were added to the atmosphere. This lowered global air temperatures: volcanic eruptions- hazards. Ash cloud so dense that solar radiation is reflected back to space resulting in short term global cooling. Water vapor and carbon dioxide create greenhouse effect resulting in warming. Emitted acids can contribute to acid rain. All 4 engines failed: pompeii- city buried under 13-20 feet of volcanic ash after mt. About 3 million people live in this area now. Factors affecting viscosity: temperature, volatile content, silica content: 3 types of lava flows, basaltic (mafic chemistry, low silica content) Very low viscosity when first emerging from the ground due to high heat and low silica content.
