Term
| Why are earthquakes dangerous? |
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Definition
-heaving objects disrupted by shaking (buildings)
-fires that result |
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Term
| Why are hurricanes dangerous? |
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Definition
| the water causes storm surges and flooding |
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Term
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Definition
| reducing the expected costs involved with Earth's hazards |
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Term
| How do you mitigate earthquake damage? |
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Definition
| reduce dependence on fragile buildings |
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Term
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Definition
| places where magma reaches Earth's surface |
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Term
| What are volcanic eruptions? |
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Definition
| they occur when the magma reaches the earth's surface |
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Term
| What two types of volcanoes are there? |
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Definition
-Passive style which have a shield shape and produce black rock called basalt
-explosive style which have a strato shape and produce rock like granite called andesite |
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Term
| Where do most volcanoes occur? |
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Definition
-along the volcanic belts of the pacific basin
-as linear/curved belts on land
-on island arcs |
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Term
| What kind of volcanoes are most typical of the Ring of Fire? |
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Definition
| andesite-producing volcanoes |
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Term
| How do volcanoes benefit us? |
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Definition
-part of earth's climate regulation
-provide raw materials for rich soil |
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Term
| how can we study the gases produced by volcanoes? |
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Definition
| by studying vesicles in basalt rocks that used to hold gas, or by collecting it directly from a volcanic vent |
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Term
| what gases come out of volcanoes and in what proportions? |
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Definition
| in decreasing proportions: water, carbon dioxide, sulfur, and others |
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Term
| What does the carbon cycle do? |
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Definition
-it transports carbon from the atmosphere to rocks via rain
-global volcanism returns carbon from rocks to the atmosphere |
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Term
| Why do volcanic eruptions cause short-term cooling of the atmosphere? |
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Definition
| it results from sulphur and volcanic ash lifted into the stratosphere and circulated around the globe |
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Term
| where are the richest soils located geographically? |
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Definition
-not in tropical regions or cold climates; tropical regions near a recent volcanic eruption are an exception.
[image] |
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Term
| What are the hazards of explosive volcanic eruptions? |
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Definition
| flying debris; induced landslides; pyroclastic flow; lahars; and lava flow |
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Term
| How does the presence of water at the top of volcano affect its eruptions? |
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Definition
-if its present, then a lahar will result when it erupts
-if its not, then a pyroclastic flow will result. |
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Term
| What is a pyroclastic flow? |
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Definition
| hot, dry rock that rolls down the volcano at high speeds |
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Term
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Definition
| it is the debris and rock mixed with water that flows down the volcano |
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Term
| What unique damage do pyroclastic flows cause? |
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Definition
| they create ash that can lead to structural failure if mixed with rain |
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Term
| Why are andesitic volcanoes explosive and basaltic ones aren't? |
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Definition
-the magma viscosity of basaltic eruptions is low. There isn't any built up pressure, so the magma will flow out at a slower pace
-andesitic volcanoes have high viscosity magma which creates a lot of built up pressure that eventually causes an explosion. |
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Term
| Where are most andesitic volcanoes located? |
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Definition
| above subduction zones along the Ring of Fire |
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Term
| How can we mitigate damage from volcanoes? |
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Definition
-prepare: we know where volcanoes are and where previous pyroclastic flows and lahars have occurred, so we could avoid those areas when considering new construction
-prediction: seismographs can give a window of eruption for a volcano |
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Term
| How do volcanoes cause global economic costs? |
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Definition
-ash and sulfur can reduce world temperatures by 0-2 degrees C for 1-2 years. This affects crop production
-limit airplane flights |
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Term
| How did mitigation help after the Mt. St. Helens eruption? |
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Definition
| it saved ~5000 people, and only 57 people were killed |
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Term
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Definition
| transient, dynamic event created by a rapid shear slip across a fault surface |
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Term
| What are the different types of earthquakes? |
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Definition
-normal/dip-slip fault: rock is pushed down
-thrust/reverse fault: rock is pushed up
-strike-slip fault: slabs slide horizontally rather than vertically |
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Term
| We can predict volcanoes; can we predict earthquakes? |
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Definition
|
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Term
| What is characteristic of thrust faults? |
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Definition
| they create slumps/hills in the land |
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Term
| How fast does a slip need to be in order to produce an earthquake? |
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Definition
| fast enough to create seismic waves |
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Term
| What causes the ground to shake during an earthquake? |
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Definition
| seismic waves reflecting back down from earth's surface cause the ground to shake |
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Term
| Why are earthquakes dangerous? |
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Definition
| cause buildings to fall on us; landslides; and tsunamis |
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Term
| Where do earthquakes occur? |
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Definition
| at subduction zone and other plate boundaries |
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Term
| How deep under the crust do earthquakes occur? |
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Definition
| most occur above 15km from surface; sub. zone earthquakes can occur above 40km. the deepest they can occur is 700km |
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Term
| How often do earthquakes occur? |
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Definition
| there are many smaller ones, but there's about 1 M=8+ earthquake per year |
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Term
| How's it possible for an earthquake to occur 700km deep? |
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Definition
| these earthquakes are the only ones that occur in the subductive material |
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Term
| How are the sizes of earthquakes measured? |
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Definition
| According to the richter scale magnitude is ~log10 (max Amp) |
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Term
| What magnitude earthquakes are dangerous? |
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Definition
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Term
| Why do buildings fall during an earthquake? |
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Definition
-ground beneath the building fails
-due to horizontal acceleration of the building. It causes the momentum of the top to go one way and the bottom the other. |
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Term
| How can you mitigate against building failure? |
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Definition
-shear bracing within the frame of a buildings walls
-steel framework
-wood frame
-steel-reinforced concrete |
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Term
| How much water does a person need to drink in a day? |
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Definition
|
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Term
| how much water does a person personally use in a day? |
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Definition
|
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Term
| what factors influence climate? |
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Definition
| temperature and precipitation |
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Term
| How much water is necessary to produce everything one person consumes in a day? |
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Definition
|
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Term
| How is earth's water distributed? |
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Definition
-3% fresh, 97% salty
-the fresh is .3% surface water, 68.7% in icecaps, 30% in groundwater
-the the fresh surface water is 87% in lakes, 2% in rivers, 11% in swamps |
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Term
| How much water is mvoed via water fluxes between reservoirs in a year? |
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Definition
| the equivalent of 1m off the world's oceans |
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Term
| How much rain falls in michigan each year? |
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Definition
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Term
| How much rain falls in the Dakota grasslands? |
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Definition
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Term
| Why's it important to know about terrestrial biomes? |
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Definition
| it helps us see high yield agriculture potential |
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Term
| What causes the ground beneath a building to fail during an earthquake? |
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Definition
-landslides
-differential soil compaction
-liquefaction |
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Term
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Definition
| natural variations in rain that lead to too much water for the river to contain, causing flooding. |
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Term
| Which terrestrial biomes have the highest agricultural yield potential? |
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Definition
| temperate grasslands and deciduous forests |
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Term
| How do dams negatively impact mitigation efforts? |
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Definition
| although they reduce the risk from small floods, they increase the damage from large floods because no one expects a large flood below the dam |
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Term
| What's a river watershed? |
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Definition
| Its made up of the land area that drains into a river |
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Term
| What are some natural flood controls? |
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Definition
-ground infiltration
-river flood plains reduce the speed of the flow of water, which reduces the peak river levels downstream |
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Term
| How do artifical levees increase the damage from river flooding? |
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Definition
| they channelize water flow, which increases the speed of the flow. This reduces the lag time to and increases the magnitude of peak river flow |
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Term
| How much rain falls in the arizona desert each year? |
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Definition
|
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Term
| how are floods beneficial? |
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Definition
| replenish groundwater; distribute sediments that enrich soil |
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Term
| why are floods dangerous? |
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Definition
| because we build permanent structures in floodplains, which can lead to large economic and human loss. |
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Term
| What weather conditions can dramatically increase precipitation? |
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Definition
| -unseasonably cool dry air from the north combined with warm, moist air from the south leads to much greater precipitation |
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Term
| How can we mitigate damage from floods? |
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Definition
| combination of land use planning and enforcement/incentives in order to discourage building permanent structures in the floodplain |
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Term
| What are the different types of motion of plate tectonics? |
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Definition
-divergent: 2 plates slide away from each other
-transform: 2 plates grind past each other along transform faults
-convergent/subduction zone: 2 plates move toward each other |
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