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15 Cards in this Set
- Front
- Back
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What is the crust? Properties of the 2 types of crust? |
Crust: Rock layer forming upper part of lithosphere CONTINENTAL crust is granitic rock that is 30-50km deep but is of low density. OCEANIC crust is basaltic rock that is 6-8km deep but is of high density |
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What is the asthenosphere? What is the core and its properties? |
Asthenosphere: Partially molten rock. The flows within the asthenosphere affect lithosphere above, causing earthquakes and volcanoes. Convection currents occur within the lower mantle, which rise from earth's core and are strong enough to move tectonic plates Core: Made of inner and outer. Outer is liquid, Inner is sold. Consists of iron and nickel. Between 4000 to 5000 degrees. |
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Explain how the core's internal heat source drives plate motion and generates magnetic field |
High temperatures in the core caused by gradual radioactive decay cause rising limbs of material called convection currents to rise and fall, moving the tectonic plates apart. A magnetic field is caused by the liquid iron in the outer core flowing around, generating a magnetic field |
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Properties of Destructive plate & where found? |
Denser basaltic oceanic plate subducts underneath granitic continental plate. As the oceanic plate sinks, it melts and forms magma. An ocean trench is also created. Collision of two plates buckle to form fold mountains as found in the Andes. Friction of subduction releases pressure in the form of earthquakes. Magma rises through surface through weaknesses in continental crust, forming composite volcanoes Found where Nazca meets South American plate |
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Properties of Constructive plate & where found? |
Two plates move apart, new basaltic material rises to the surface to form new seabed. Fissures and faults created on surface where magma can reach. Chain volcanoes made in oceanic ridge, as seen in Iceland. Earthquakes caused by the pressure of the friction, but small and not harmful. Forms shield volcanoes. Found where Eurasian plate separates slowly from North American plate. There is a mid Atlantic ridge in Iceland from this. |
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Properties of Conservative plate & where found? |
Plates slide past one another at differing speeds. No plates created/destroyed = no magma = no volcanoes. Earthquakes are caused by the pressure from the friction. Size of earthquake relates to frequency. Longer period w/o earthquake = higher pressure = higher magnitude. Found on North American and Pacific plates Found at San Andreas Fault, Los Angeles. |
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Properties of Shield volcano? where found? Properties of Composite volcano? where found? |
Shield: Gentle slopes. Basaltic. Common but rarely violent. Mauna Loa, Hawaii. Composite: Steep slopes. Andesitic. Infrequent but violent. Mt. Pinatubo, Phillipines. |
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How far are people vulnerable from earthquakes? What is their capacity to cope? |
Vulnerability: Not likely to be threatened by lava or pyroclastic flows. May be affected by clouds of volcanic ash. Capacity to cope: Sakurajima volcano closely monitored and evacuation plans are in place. |
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Primary and Secondary impacts of Haiti 2010? |
Primary: 316,000 deaths. 300,000 injured. Over 50 hospitals destroyed. Secondary: 1,000,000 homeless. Cholera spread due to lack of sanitation. Damage to road/ports stopped trade. |
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Primary and Secondary impacts of LA 1994? |
Primary: 57 deaths. 9000 injured. 11 hospitals structurally damaged. Secondary: 2 aftershocks with magnitude 6.0 occurred. 100 fires caused by broken gas pipes (from houses shifting from foundations). 200 cases of Valley fever broke out from inhaling large clouds dust that carried spores. 3 died from it. |
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Primary Social/Economic and Secondary Social/Economic impacts of Montserrat 1995-1997? |
Primary Social: 11,000 was evacuated to north of Montserrat. 19 killed as people chose to stay and watch. 200 homes destroyed. Primary Economic: Farmland were destroyed by pyroclastic flows. Airport destroyed. Businesses destroyed. Secondary Social: 50% of population left Montserrat. Respiratory problems were caused by acid rain. Floods occurred when valleys were covered in ash. Secondary Economic: Tourism declined by 46%. 50% unemployment rate. Flights were cancelled due to ash and gas in air. |
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Role of prediction, warning, evacuation in volcanoes. |
Prediction: Seismometers tell us when eruption is imminent. Tilt meters record changes in volcano's shape. Warning: Small earthquakes from rises of magma through cracks. Volcanoes release gases when it nearly erupts. Evacuation: Evacuation routes and zones as happened in Mt. Pinatubo in 1991. |
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Role of prediction, warning, evacuation in earthquakes. |
Prediction: Foreshocks, as used before 1975 Haicheng earthquake which measured 7.2 magnitude. Seismic history like they do in El Salvador. Warning: None, but strange behaviour from animals. Evacuation: Evacuation plans and earthquake drills and alarms, such as Los Angeles. |
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Relief Efforts Kashmir 2005 |
Short term: Schooling in tents. Red Cross sent 21,500 blankets and 300 kitchen sets. Aid workers from NATO helped the injured Long term: Red Cross brought back water supply to Kashmir. Homes were rebuilt from tin. UN gave $95,000,000 in aid |
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Mitigation in the developed and developing world |
LA: Large concrete weight on top of building activated by computer controlled dampers. Moves in opp direction of earthquake, counteracting stress on structure. Large rubber shock absorber in foundations allow buildings to move about without damaging structure. Cross bracings to make building more ductile. Pakistan: Concrete ring ties walls to foundations to reduce damage. Lightweight roofs to reduce impact. Cross braced wood for ductility. |
