Lesson&2:&Energy&Sources&Overview&• Most&geologic&disasters&involve&the&release&of&large&amounts&of&energy&either&quickly&or&slowly.&To&understand&these&processes,&we&need&to&know&where&the&energy&released&was&derived&from.&Overview&• Conserva)on*of*Energy:*energy,'like'ma-er,'is'neither'created'nor'destroyed.&• When&energy&drives&a&geologic&process&it&is&being&converted&from&one&form&to&another,&e.g.&potenDal&energy&to&kineDc,&gravitaDonal&to&kineDc,&etc.&&• During&each&one&of&these&conversion s,&there&is&loss&of&energy&to&dissipaDve&forces&such&as&fricDon.&Energy&loss&here&means&that&the&energy&is&no t&abl e&to&perform&useful&work,&i.e.&make&something&happen.&It& is&si mpl y&lost&to&the&surroundings&generally&in&the&form&of&heat.&Overview&• There&are&four&primary&energy&sources&for&the&processes&that&cause&geologic&hazards.&They&are:&– the&Earth's&internal&heat;&– solar&energy&from&the&Sun;&– gravitaDonal&energy&of&the&SunJMoonJEarth&system;&and&– the&impact&of&terrestrial &bo di es.&Overview&• There&are&three&sources&of&internal&energy:&&&&– residual*heat:&energy&trapped&inside&the&Earth&it&grew&due&to&impacts&&– gravita)onal*energy:&energy&released&as&core&and&mantle&of&Earth&formed&as&heavy&elements&moved&to¢er&and&lighter&ones&to&outside;&and&&– radioac)ve*decay;&heat&released&as&radioacDve&elements&(U,&Th,&K)&undergo&spontaneous&decay.&&Overview&• Heat&is&energy&that&moves&from&high&temperature&to&low&temperature.&&• In&the&Earth,&internal&energy&moves&from&the&inner&part&of&the&planet&to&its&outer&rim&in&one&of&two&ways:&– conduc)on:&is&transfer&of&heat&by&vibraDon&of&atoms&on&the&atomic&level.&It&occurs&in&solids&without&the&movement&of&a&fluid,&conducDon&is&the&dominant&heat&transfer&mechanism&in&the&crust,&the&outer,&thin&rim&of&the&planet.&– convec)on:&the&movement&of&heat&with&a&flowing&fluid.&ConducDon&is&the&primary&manner&in&which&heat&is&transferred&in&the&core&and&mantle.&Large&convecDon&cells&move&hot&material&from&the&interior&toward&the&base&of&the&crust.&– Of&these&two&pro cesses,&conducDon&is&a&much&slower&means&of&heat&transfer&than&convecDon.&Overview&• Internal*Energy*Driven*Processes:*– volcanoes&&– earthquakes&&– plate&moDon&&– mountain&b ui ldi ng&&• These&processes&create&new&land&masses&as&well&as&landforms.&Hence,&they&are&known&as&cons truc)ve*processes.&&&Overview&• There&are&three&sources&of&external&energy:&&&&– solar*energy:&radiant&energy&from&nuclear&fusion&in&the&Sun&that&strikes&the&Earth;&&– )dal*energy;&external&gravitaDonal&energy&associated&with&the&movement&of&planetary&bodies&in&the&SunJEarthJMoon&system;&and&&– impact*energy:&transfer&of&the&kineDc&energy&of&a&moving&planetary&object&to&the&Earth&when&it&impacts&the&surface,&some&of&the&energy&is&dissipated&by&sound&waves,&some&turns&to&heat&that&melts&rock&and&some&is&converted&to&tsunami&&Overview&• Solar*Energy:**– Of&the&three&sources&of&external&energy,&solar&energy&is&by&far&the&most&important.&&– It&drives&the&surface&processes,&e.g.&erosion,&transport,&weathering ,&etc,&that&affect&rocks&exposed&at&the&Earth's&surface.&&– This&energy&evaporates&water&to&produced&weather&and&creates&temperature&differences&that&produce&the&movement&of&both&wind&and&water.&&– These&processes&destroy&or&modify&exisDng&landfo rms&and&rocks,&transport&the&breakdown&products&and&create&new&rocks.&Overview&• External*Energy*Driven*Processes:*– storms&&– flooding&&– erosion&&– sea&level&rise&&– Drought&– storm&surges&&• These&processes&modify&and&destroy&preJexisDng&land&masses&as&well&as&landforms.&Hence,&they&are&known&as&destruc)ve*processes.&&&Types&of&Energy&• ENERGY&is&what&drives&everything&in&the&universe.&It&powers&geologic&processes,&events&that&produce&geologic&hazards&and&the&processes&of&industrialized&socieDes.&Some&of&the&types&of&ENERGY&include:&– kineDc&energy&&– potenDal&energy&(gravitaDonal,&magneDc,&electric)&&– chemical&energy&&– mass&energy&– thermal&(internal)&energy&&Types&of&Energy&• KineDc&Energy&– Kine)c*energy&is&the&ENERGY&associated&with&moving&mass.&Any&body&in&moDon&h as&kineDc&energy.&The&kineDc&energy&of&a&body&of&mass,&m,&and&traveling&at&a&velocity&v&is:&&&Types&of&Energy&• KineDc&Energy&– KineDc&energy&can&be&converted&to&work&that&affects&its&surroundin gs.&Th e&conversion&is:&Types&of&Energy&• Poten)al*energy&is&the&energy&associated&with &the&posiDon&of&a&body&in&a&force&field.&The&force&field&can&be&electric,&magneDc&or&gravitaDonal&although&the&most&important&for&geologic&processes&is&the&la[er.&The&potenDal&energy&of&an&object&in&a&gravitaDonal&field&is:&Types&of&Energy&• Poten)al*energy*– PotenDal&energy&is&closely&Ded&to&kineDc&energy. &&– PotenDal&energy&plays&an&important&role&in&energy&consumpDon&and&geologic&hazards.&Types&of&Energy&• Chemical&reacDons&involve&the&reordering&of&bonds&between&the&reactants&and&products.&The&energy&is&these&bonds&represents&chemical*energy.&ReacDons&either&require&energy&to&proceed&or&release&energy&on&compleDon.&&&Types&of&Energy&• Mass*energy&is&the&energy&released&by&changes&in&the&nucl ei&of&an &atom,&i.e.&nuclear&reacDons.&The&special&theory&of&relaDvity&proposed&by&Einstein&describes&the&relaDon&between&the&energy&released&and&the&amount&of&mass&converted.&The&famous&equaDon&is:&Types&of&Energy&• Electromagne)c*energy,&also&know&as&radiant&energy,&is&energy&carried&by&waves.&The&energy&in&electromagneDc&waves&is&inversely&proporDonal&to&its&wavelength,&but&directly&proporDonal&to&Plank's&constant&(h)&and&the&speed&of&light&(c).&Types&of&Energy&• Thermal*(internal)*energy&is&energy&expressed&by&the&random&moDons&of&the&molecules&or&atoms&that&make&up&a&substance&or&object.&The&greater&the°ree&of&moDon,&the&higher&the&thermal&energy&of&the&object.&• Thermal&energy&is&closely&related&to&temperature.&The&greater&the&temperature&of&an&object,&the&higher&is&thermal&energy.&Conversely,&low&temperature&means&low&thermal&energy,&i.e.&small &random&moDon.&&• It&is&important&to&remember&that&temperature&is&a&measure&of&the&thermal&energy&state,&but&is¬&equivalent&to&thermal&energy.&&•
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