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Explore past earthquakes, direct/indirect effects, and risk assessment. Learn about seismic simulators and reducing seismic risk through vulnerability evaluation. Discuss the impact of natural and technological catastrophes. Analyze the seismic risk components and the potential impact on Lisbon.
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Module: Seismicityandseismicrisk (for civil engineers) Mário Lopes (mlopes@civil.ist.utl.pt) Departamento de Engenharia Civil, Arquitectura e Geo-Recursos do Instituto Superior Técnico, Lisboa Bolonha, 3-6 March 2014
2.2 – Global impact of earthquakes • Types of earthquake effects: direct and indirect effects • Past earthquakes • Comparison with impact of other natural and technological catastrophes • Risk = hazard x exposition (people and economic assets exposed to seismic damage) x vulnerability • The future – earthquake simulators.
Earthquakes - affectlargeareasof a territory. For instanceseffectsof tsunamis can reach zones manythousandsofkilometersawayfromtheepicenteroftheearthquakethattriggersthe tsunami. Ex: Samatra , 2004 Othertechnologicalor natural events: Explosions – affectsmallerareas Car acidents– uniformlydistributedalong time
Indirect / Directdamage Indirectdamage– damagecauseddirectlybytheearthquake, triggerschainreactionsleading to much more damage. Ex: economicalactivitiesaffectedbydisruptionoftransportationsystemsorlackofsupplyofenergy, waterorgas.
Directdamage- includestotal or parcial collapseofbuildings, lifelines industrial facilitiesandbuilt cultural heritage, humanvictims, deadandwound, as well as phsicologicaltraumas onsurvivors. Imaterial effects– effectsthat are almostimpossible to quantify, for instanceschanges in cultural values, religion, aesthetic, politics, dislocationofpopulation, etc. Ex: Portugal, Azores, 1973, whentheislandsof Pico and Faial losthalfoftheirpopulationafteranearthquake, andTurkey, 1999, as theeconomiclossesworsenedtheeconomicsituation, contributing to a politicalchange later on.
PastearthquakesStatistics (officialstatistics)
Geographicdistributionofearthquakesandvictims causes ofdamage
Observedand future tendencies – increasingpopulation in largecities, manyofthem in earthquakeproneareas in developing countries wherequalityofconstructionisnotreliable increasingnumberofvictims - Increasingeconomicdamagesobserved in developed countries (Northridge, 1994, Kobe, 1995) lesstoleranceofpublicopinions to economicdamage more stringentcodes requisites to controleconomicdamage more emphasisonvariablesthatassesseconomicdamage (displacements) + nonethelessmore economicdamage(?)
Comparison with impact of other natural and technological catastrophes Energyreleased
Mortality rates for severaltypesofcatastrophes for thelast 30 years Earthquakes Draughtsandhunger Floods Hurricanes Landslides Volcanoes Others
Earthquakerisk = Hazard x Exposure x Vulnerability Hazard – probabilityofoccurrenceofearthquakesofcertaincharacteristicisduringcertainperiodsof time Exposure – peopleandbuiltenvironmentexposed to earthquakes Vulnerability – seismicresistanceofthebuiltenvironment Reductionofseismicrisk: Man (engineers) can actuponvulnerability
Seismicsimulators Mathematicaltoolsthatsimulateseismiceventsandevaluatesitseffects Definitionofseismicevent Epicenter Magnitude Seismicsource Wavepropagation Site effects Buildings Otherfacilities Population Vulnerability Evaluationof: damage victims
LNEC earthquakesimulator Scenario: repetitionofthe 1755 earthquakenowadays
LNEC earthquakesimulator Scenario: repetitionofthe 1755 earthquakenowadays
Othertools to predicttheeffectsof future earthquakes: Comparisonswithearthquakesof similar magnitude and epicentral distances in regionsof similar economicdevelopment Conclusions for Lisbon: similar to theonesof LNEC earthquakesimulator