Bolonha, 3-6 March 2014 Module: Seismicity and seismic risk (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.

Explosions – affect smaller areas Earthquakes - affect large areas of a territory. For instances effects of tsunamis can reach zones many thousands of kilometers away from the epicenter of the earthquake that triggers the tsunami. Ex: Samatra , 2004 Other technological or natural events: Explosions – affect smaller areas Car acidents – uniformly distributed along time

Indirect / Direct damage Indirect damage – damage caused directly by the earthquake, triggers chain reactions leading to much more damage. Ex: economical activities affected by disruption of transportation systems or lack of supply of energy, water or gas.

Direct damage - includes total or parcial collapse of buildings, lifelines industrial facilities and built cultural heritage, human victims, dead and wound, as well as phsicological traumas on survivors. Imaterial effects – effects that are almost impossible to quantify, for instances changes in cultural values, religion, aesthetic, politics, dislocation of population, etc. Ex: Portugal, Azores, 1973, when the islands of Pico and Faial lost half of their population after an earthquake, and Turkey, 1999, as the economic losses worsened the economic situation, contributing to a political change later on.

Past earthquakes Statistics (official statistics)

Geographic distribution of earthquakes and victims causes of damage

Observed and future tendencies – increasing population in large cities, many of them in earthquake prone areas in developing countries where quality of construction is not reliable  increasing number of victims - Increasing economic damages observed in developed countries (Northridge, 1994, Kobe, 1995)  less tolerance of public opinions to economic damage  more stringent codes requisites to control economic damage  more emphasis on variables that assess economic damage (displacements) + nonetheless more economic damage (?)

Comparison with impact of other natural and technological catastrophes Energy released

Mortality rates for several types of catastrophes for the last 30 years Earthquakes Draughts and hunger Floods Hurricanes Landslides Volcanoes Others

Earthquake risk = Hazard x Exposure x Vulnerability Hazard – probability of occurrence of earthquakes of certain characteristicis during certain periods of time Exposure – people and built environment exposed to earthquakes Vulnerability – seismic resistance of the built environment Reduction of seismic risk: Man (engineers) can act upon vulnerability

Definition of seismic event Seismic simulators Mathematical tools that simulate seismic events and evaluates its effects Definition of seismic event Epicenter Magnitude Seismic source Wave propagation Site effects Buildings Other facilities Population Vulnerability Evaluation of: damage victims

LNEC earthquake simulator Scenario: repetition of the 1755 earthquake nowadays

LNEC earthquake simulator Scenario: repetition of the 1755 earthquake nowadays

Other tools to predict the effects of future earthquakes: Comparisons with earthquakes of similar magnitude and epicentral distances in regions of similar economic development Conclusions for Lisbon: similar to the ones of LNEC earthquake simulator