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Algerian – Japanese Scientific Gathering, University of Sciences and Technology Houari Boumediene, Algiers, Algeria LEARNING FROM EARTHQUAKE DISASTERS: The case of Algeria CHEMROUK, M. Professor of Materials and Structural Engineering, Faculty of Civil Engineering, University of Sciences and Technology Houari Boumediene (USTHB), Algiers, Algeria. Tel: 213 21 243410; Email: [email protected] Abstract An earthquake is expressed on the soil surface by vibrations. These vibrations are caused by shockwaves induced by rock cracking deeper under the soil surface at the earth crust. This cracking is due to the accumulation of huge quantities of energy which is suddenly released, creating fracture of the rocks as their ultimate mechanical rupture is reached. It is believed that this energy accumulation is caused by the movement of the plates on both sides of a separating fault at the crust level. The damage observed on the soil surface, and hence on civil engineering constructions as a result of the shockwaves, depends on the amplitude, on the frequency and on the duration of the vibrations. The particularly disastrous earthquakes that have struck the northern part of Algeria in the past have caused many losses of lives and induced significant damages to the building sector. They significantly disturbed the development activities of the region and represent an important parameter that should be taken into consideration for any proposed new housing settlement or economical investment. This seismic activity should be a clear signal that the region is continuously prone to major seismic risks. It is necessarily, then, to protect the population from disastrous consequences by improving the construction qualities and setting up intervention strategies in the aim of managing the disaster when the seismic hazards strike. In this sense, disaster preparedness is a very important strategy which makes the population aware of the risk. Based on past seismic disasters, this paper focuses on what should be gained and learned from past earthquakes in the aim of improving, first the construction quality, and then, the intervention strategies in seismic hazard regions, with a particular emphasis on the disastrous effects of the 2003 Boumerdes –Algiers earthquake, considered as severe ground motion that has affected a population of about 4 million inhabitants, 2300 of whom have died, 11500 have been injured, many handicapped for life and about 100.000 left homeless. As for the material damages, 150.000 homes have been affected, 10% of these homes have completely collapsed or needed to be demolished and 40% having serious structural damages. Indeed, in structural engineering there is always a risk that failures may occur and when they do occur, the causes and defects should be thoroughly examined and brought together in order to learn lessons and widen the knowledge to other engineers.