ABSTRACT
Located at the northern tip of Africa, on the limit of an active tectonic plate, Algeria is subjected to quite frequent and sometimes violent earthquakes, such as the earthquakes of 1776 (20,000 dead in the region of Algiers), 1825, 1869, and more recently the earthquakes of 1954 (Magnitude 6,8), 1980 (Magnitude 7,7 in El Asnam) and 2003 (Magnitude 6,8 in Boumerdes), as well as much more recent earthquakes in Algiers, Bouira, Medea and Skikda. According to the CRAAG (Centre for Research in Astronomy, Astrophysics and Geophysics in Algiers), an average of 10 earthquakes of magnitude equal to or greater than 3 on the Richter scale are felt every month in northern Algeria. It needs to be remembered that this centre provides its expertise and experience in all fields of seismology and supervises research in this domain. The National Agency for Dams and Transfers (ANBT), placed under the Ministry of Water Resources, is in charge of the series of 84 large dams and hydraulic infrastructures of Algeria: the ANBT must therefore ensure the safety of these dams even in the event of extreme earthquakes. Each time an earthquake occurs, the ANBT is questioned by the media and the government about the capacity of dams to behave adequately during earthquakes. The impounding of the Beni Haroun dam, key element of the storage and water transfer project from the north towards the Constantine plateau and the south, has started in 2003. Normal water level was reached for the first time in February 2012. This dam of strategic importance for the region is in an area that recent studies have proven to be highly seismic. At the request of the ANBT, the Algerian design office Coyne and Bellier el Djezair, with the support of Tractebel France and under the guidance and control of a Panel of Experts chaired first by Raymond Lafitte and then Bernard Tardieu, carried out a detailed assessment of the seismic risk associated with the Beni Haroun dam. With the participation of the CGS (Algerian National Centre for Applied Research in Earthquake Engineering), which carried out the assessment of the seismic hazard of the region, the study presented in the two following articles is highly instructive and shows that the Beni Haroun dam displays a satisfactory behaviour even for an extreme earthquake, at the cost of some adjustments. As General Director of the ANBT, I am particularly pleased with the approach followed and I am very proud to sign the introduction of these two articles, which honour Algeria and its Engineering.
