The Melouza (Algeria) earthquake of 21 February 1960

The Melouza earthquake of 21 February 1960 is one of the largest earthquakes, in terms of casualty and damage, that the Hodna region has experienced since the beginning of this century. The main shock, which lasted about 5 seconds, caused the loss of 47 lives, injured 129 and rendered approximatively 4,900 homeless (about 700 families); it destroyed about 600 housing units. the poor quality of the constructions and their low resistance to seismic forces are the main causes, of the high damage rates in Algerian earthquakes. The earthquake was felt in an area of about 20,000 km2. Macroseimic data retrieved from contemporary sources show that the area most effected was the whole zone between Melouza and Beni Ilman where the main shock exhibited maximum intensity at I0 = VIII (MSK). From the intensity data, an isoseismal map of the main shock was drawn and a macroseismic epicenter located, at 36.03°N, 4.17°E, between Melouza and Beni Ilman. The surface-wave magnitude was calculated at MS=5.10 (±0.30). Although the damage and casualties were reported as due to the main shock, the possibility of cumulative damage from the heavvy rain and earliar aftershocks remains. According to the different sources available, the main shock was not proceded by any foreshock or any other premonitory signs. On the other hand, the earthquake was followed by a long sequece of aftershocks. The 1960 Melouza earthquake also trigged important landslides and rockfalls. The total cost of damage was estimated, at the time, as 500 million French Francs. This work shows that source documentary materials must be analyzed with great care with respect to the socio-economical situation, demographic conditions as well as the religious and cultural backgrounds. This workil directly ralated to the importance of the seismic characterization of the mediterranean basin for disaster mitigation and emergency planning in the region.