Natural Disasters Essay

949 Words Oct 14th, 2014 4 Pages
Natural Disasters * What drives the hydrologic cycle? – energy from the sun * What is the most common trigger for avalanches in recreational accidents? – * The Calgary Flood of 2013 was primarily the result of – heavy rainfall in Rockies
Natural Processes and Energy Sources * Processes - physical, chemical, and biological ways in which events affect Earth’s surface * Internal processes come from forces within Earth * Plate tectonics * Result of internal energy of Earth * External processes come from forces on Earth’s surface * Atmospheric effects * Energy from the sun
Definitions
* Hazard – probability that a specific damaging event will happen within a particular period of time
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tion, land-use, population) * Magnitude-Frequency Concept * Inverse relationship between magnitude and frequency * M = Fe-x * The history of an area gives clues to its potential hazards * Maps, historical accounts, weather and climate data * Rock types, faults, folds, soil composition
Geologic Cycle * Geologic conditions govern the type, location, and intensity of natural processes * Sub-cycles * Tectonic cycle * Rock cycle * Hydrologic cycle * Biogeochemical cycles
Rock Cycle * Rocks are aggregates of one or more minerals * The rock cycle refers to recycling of three major rock types * Different rocks are formed by different processes * Rock types in a location give clues to the geological past and present * Igneous rocks * Form from crystallization of magma * Sedimentary rocks * Rocks are weathered into sediment by wind and water * Deposited sediment is converted into sedimentary rock by lithification * Metamorphic rocks * Rocks are changed through extreme heat, pressure or chemically active fluids

Hydrologic Cycle * Solar energy drives movement of water between atmosphere and oceans and continents * Processes include: evaporation, precipitation, surface runoff, and subsurface flow * Water is stored in compartments such as oceans, the atmosphere, rivers, streams, etc * Residence time is the estimated average time that a

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