Name ________________________ Lab 1. Volcanic Hazards VOLCANOES INTRODUCTION Few things excite the imagination as much as a volcanic eruption‚ one of nature’s magnificent spectacles‚ which can result in devastating consequences. The very word “volcano” brings to mind thunderous explosions‚ rivers of fiery orange lava‚ and images of smoking destruction. The actual capacity for destruction is not overrated -- volcanic eruptions are one of the most devastating of all geologic hazards. There
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Geology Notes: 9/5/2013 SI SESSIONS held in Old main or State Monday: 945-1045 Tuesday: 1015-1115 Thursday: 4-5 Melissa Allen (email is on syllabus) Notes are on geology webpage faculty and staff -> Dr. van Hees -> course notes LECTURE: Plate Tectonics Chap.2 -Until ~1915 people thought continents were stuck were they are and they didn’t move. Why did ideas change? -Wegener’s proposed the theory of Continental Drift It proposed that all continents move and that at one time
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naked eye o Texture: small crsytals (can’t see) dull o Cooling: cooled quickly; Extrusive • Phaneritic: all materials are visible to the naked eye o Texture: large crystals; shiny‚ sparkly o Cooling: cooled slowly; Intrusive Know the texture‚ magma/lava composition‚ rock forming
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GEOLOGY 101 Exam 1 Study Guide Geology | * The science that examines Earth‚ its form and composition‚ and the changes that it has undergone and is undergoing * The processes are slow‚ but none the less dynamic * Physical geology: examines Earth materials and seeks to understand the many processes that operate on our planet * Historical geology: seeks an understanding of the origin of Earth and its development through time | Scientific Method | * It is a rigorous process whereby new
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philippines on june 15 1991. in march and april 1991 magma rising towards the surface from more than 30 km below pinatubo started making small earthquakes and caused small powerful steam explosion that opened three craters on the north flank of the volcano. thousands of small earthquakes occurred and many tons of gas were also emitted by the volcano. from june 7 to june 12 the magma reached the surface of mount pinatunbo. because of the gas pressure the magma erupted out with an amazing strength but did
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around 50 to 100km in diameter on average and has a huge bubble of sticky magma beneath it‚ tens of kilometres across that is trapped under overlying rock and with gases such as sulphur dioxide‚ water vapour and carbon dioxide trapped in it. They are formed near destructive plate boundaries where material from a plate that is descending rises back to the surface‚ this magma then rises up creating the large bubble of magma below the overlaying rock. They are also formed at continental hotspots‚
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problems the next time an eruption seems likely. 7. Prediction‚ forecasts and reactions - Active volcanoes all over the world are monitored using a vast array of scientific equipment. Satellites look for infrared radiation that indicates rising magma and ground instruments measure gas emissions‚ ground deformation and resulting earthquake activity. - Geologists use evidence from past eruptions to suggest likely eruptive scenarios and hazard maps can be constructed to indicate those areas at greatest
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factor that must be considered is the viscosity of the magma. The viscosity can determine how violent the eruption is and what shape the volcano becomes. Viscosity can be affected by temperature‚ dissolved gases in the magma and its silica content. High temperatures can make the magma less dense allowing it to flow more easily. The amount of dissolved gases lowers the viscosity. Lastly a high silica content will make the magma more viscous. Magma of a high viscosity can cause very violent eruptions
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There are two types of plate margin. When there is a boundary between two diverging tectonic plates‚ such as between the North American and Eurasian plates‚ it is known as a constructive plate margin. This is because it recognises the importance of magma rising up from the mantle to create new crustal rock. The boundary between two converging plates is known as a destructive plate margin‚ as it is responsible for more violent seismic activity‚ volcanoes and high mountain ranges. Destructive Plate
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activity is usually found along oceanic ridges where plates are moving apart‚ near rift valleys‚ on subduction zones where the most violent activity takes place and over hot spots which have given rise to the Hawaiian islands. Magma is generated at most plate boundaries‚ and this magma rises to the surface to form volcanoes. The mobility of crust also causes earthquakes. When plates collide or slide past each other‚ it leads to generation and accumulation of pressure (strain) which when released causes
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