1. Bolonha, 3-6 March 2014 Module: Seismicity and seismic risk
(for civil engineers)
Mário Lopes
Departamento de Engenharia Civil, Arquitectura e Geo-Recursos do Instituto Superior Técnico, Lisboa
Bolonha, 3-6 March 2014

2. 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.

3. 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

4. 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.

5. 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.

6. Past earthquakes Statistics
(official statistics)

7. Geographic distribution of earthquakes and victims
causes of damage

8. 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 (?)

9. Comparison with impact of other natural and technological catastrophes
Energy released

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

11. 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

12. 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

14. LNEC earthquake simulator
Scenario: repetition of the 1755 earthquake nowadays

15. LNEC earthquake simulator
Scenario: repetition of the 1755 earthquake nowadays

16. 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