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Nat Hazards Exam 2
Natural Hazards Midterm
| Question | Answer |
|---|---|
| Richter Scale | Invented in the 1930's and originally was a measure of amplitude. Logarithmic (increase in amplitude is ten fold stronger up each one). Ex: 3.0 has 10x the amplitude of a 2.0 |
| Moment Magnitude Scale | Measures the height of wave (amplitude) but also the energy released to create such an earthquake. |
| Mercalli Scale | Corresponds to the Richter Scale but puts human impact like structural damage and human reactions to it. |
| Volcanic Explosivity Index | Scale from 0-8, 8 being rare and catastrophic and 0 being non explosive (no ejection of lava, slow trickle). Takes into account the height of eruption column (how high lava is spewed). |
| Mt St Helens (1980) | Moderate sized earthquake that set in motion the eruption which also caused a landslide moving the whole top of the mountain off, killing 57 people. |
| Mt Pinatubo (1991) | eruption that erupted into the atmosphere which circulated the globe leading to global temperature drops for a year or two. Killed 1,500 people in the local vicinity and created a crater lake bc of the eruption. |
| Krakatoa (1883) | Indonesia eruption which had similar effects to Pinatuba. Effected the entire globe, even European equipment detected an earthquake on the other side of the world. |
| Montserrat | Ash covered this island which reached up to the second stories of buildings, was a slow cleanup and the people were evacuated. |
| Mt Vesuvius | Pompeii 79 A.D. people were cast in ash material suddenly. |
| Explosiveness | Usually can tell you how quickly the onset of a disaster is, the more explosive it is the quicker it usually is. |
| Mudflow (lahar) | Slurry of rocky debris and water, can move very quick and can kill. Ex: Large lahar killed 25,000 people |
| Ash Deposits | Damaging to public health and plants, but over a longer time scale is very good for soils making them the most productive in the world. |
| Pyroclastic Flow | Really hot gas mixed with other particles (airborne) high temperature and fast moving. Kills with heat and sheer force almost instantly (cant be outrun). |
| Tsunamis | Waves energy generated by a sudden ocean event most likely an earthquake. The energy from the earthquake or other event radiates through the water in a 600 mph wave and then near the coast a significant wave forms bc the energy needs to go somewhere. |
| Magnitude | Measures the height of a tsunami wave as it crashes into the coastline, above the normal sea level adjusted for tide. |
| Wildfires | connected to other hazards like drought. Can start by natural or human causes, but 90% of wildfires are caused by humans. |
| Heat transfer in wildfires | Convection damage casued by wind, Conduction and radiation tend to dry out nearby material which makes it easier to ignite later. |
| Fire Triangle | Fuel, Weather and Topography all interact to show how extreme a wildfire will be. |
| How can the fire triangle affect how a wildfire is? | Structure and dryness of fuel, if the surrounding area is moist due to climate so the fire needs to dry it out first before spreading, where it starts like how a grassland has less fuel then a forest. |
| Weather Fire Triangle | Drought is the highest risk time for fires. When it rains or when it doesn't. Windy areas provide more oxygen for these fires to spread easier and carry their flames further. Wind can also carry embers landing in new areas to spread more. |
| Topography Fire Triangle | Fires spread easily uphill bc heat convection rises, which preheats the vegetation uphill and ignites it quicker. South facing slopes recieve more sunlight and are at higher risk. Ridges and valleys alter wind too. |
| Wildfire Risk Index | First looks into the frequency of these events then the building value, agricultural value and population after. All of these affects are added up monetarily to get the (WRI). |
| Tornado stats based on states | Texas: Large land mass with the most tornadoes Kansas: Most likely to be hit by tornado per square mile Tennessee: Most deaths from tornados Arkansas: Most deaths due to tornado per capita |
| Hurricane spatial patterns | North of the equator the trade winds move towards the equator and West from the high South Atlantic to the low pressure equator. From Africa to the US in Florida or New Orleans. |
| Duration of Earthquake | usually related to how large it is. Small (1-4 seconds), Moderate (5-6 seconds), Large (7+ seconds). |
| Chile Earthquake | Estimated as the largest Earthquake ever, estimated at 9.5 on the richter scale and happened in the 1960's. |
| Earthquake Reflection | When a seismic wave is in the Earth being bounced, creating a mirror effect after hitting different rock and reflecting the wave back. |
| Earthquake Foreshock | First shock redubbed to this if the aftershock is stronger than it. |
| Midwest flood of 1993 | Affected a very large area, up to 200 days in some areas. Many States were affected but Missouri was the main target. Happened due to a series of below normal temps (less evapotranspiration) and high rainfall. Unusual amount of snowfall melted. |
| Duration of volcanic eruptions | Depends on magma supply, the properties of it, and the geologic structure of the volcano. I will last as long as it has a supply of magma. Viscosity plays a role in how long it lasts and if its constricted when coming out or not. |
| Diurnal | 24 hour time period to find out the distinction betwen day and night. Ex: Thunderstorms/tornadoes happen in the late afternoon or early evening bc the high temps are needed for them. |
| Rate of Onset | How quick something happens, can we prepare or protect ourselves? Ex: earthquakes are hard to predict ahead of time, but foreshocks, higher radon gas detection, and animal behavior can tell us its coming. |
| Volcanic Rate of Onset | Easy to detect through gas release, hydrologic changes and tremors. Warning comes in a matter of days before so easy to prepare or evacuate. Some places do not have tech to detect though so it is still dangerous. |
| Tornadoes Rate of Onset | Hard to predict and develop quickly, but doplar radars can analyze movements of air where tornadoes are likely to happen to detect them. |
| Location Decisions | Could be someone staying in place after repeated disasters. This could be due to a lack of fund to get out, family qnd friends live nearby, or Topophilia (love of a place). People also dont think disasters will happen to them. |
| Why People dont evacuate | People could not evacuate bc nothing happened the last time a warning was issued, lack of a place to go (no social networks), stubbornness or distrust of central authority, or a false sense of security (riding out the storm at home). |
| How is communication important for Disasters? | Lack of proper communication with people from governmental bodies or local leadership can lead to people not evacuating or not knowing what to do to mitigate. These things take a lot of coordination to recover or prepare for. |
| Behavioral approach to natural disasters | Old people may not move back to an area even after levees and dams or other preventative measures are put in place. Not worth the effort to rebuild the farm if you are retiring in 5 years and other reasons similar. |
| Bounded Rationality | When individuals make decisions, their rationality is limited by the information they have, the cognitive limits of their minds, and short time they have to make a decision. |
| Preference Model | Take surveys post disaster and see what people did do or didnt, and why they did what they did. How prepared were they did they spend money on extra insurance or not and why? Not very personal and a lot of data. |
| Situational physical factors | How many times and how badly someone has been effected by disasters plays a role in how a person reacts. Sometimes people with awareness adjust their circumstances a little bit ("meet the hazard halfway"). Daily concern vs low prob also play a big role. |
| Slow approaching disasters | A threshold that causes people to react in some way is eventually reached Ex: people in a drought cant deal with no ac anymore, or farmers altering farming to use less water. |
| Socio-economic conditions | Rich people dont have more knowledge or care about a disaster more but will invest to protect themselves bc they can. May be hard for elderly to invest in countermeasures on a fixed income. |
| Religion effect on hazards | Can have points of social networks to facilitate relief efforts. But can also be fatalistic (people deserved it). |
| Motivational Decay (window of opportunity effect) | After a while, the mitigation efforts drop, usually after 6 months. People are over it and nothing will probably be done helping or fixing. More extreme events can change this time frame. |
| Factor of primacy | How we remember a disaster, like remembering a big flood that happened 100 years ago even if it doenst apply to the types of floods we get the most or now. |
| Community Behavior | Local government cannot usually afford or fully handle dealing with a disaster, so federal funding is relied on more-so in the past then now (not better off just get less money). |
| artificial community | Formed right after a disaster, people rally and are inspired to help, doesn't last forever before peoples opinions and ideas differ again. |
| Recovery after natural disasters | Sometimes everything doesn't get put back the same, affecting poorer communities the most, where many leave and dont return. Experience, outside connection and good leadership are crucial to this. |
| Post Event effects | Spatial changes, return to normal, vulnerable communities further disadvantaged. Large costs need to be financed to rebuild. People may be inclined to get hazard insurance. Might modify the event like building dams or modify housing to make it stronger. |
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