PREDICTION OF SEISMIC INTENSITY IN URBAN AREAS. CASE STUDY OF THE CITY OF BATNA, ALGERIA

Knowledge of a non-instrumental measurement is one of the most remarkable scientific assets; unfortunately, in seismology, it is considered the least predictable, but it does play an important role in assessing seismic risk. Batna, the capital of the Aurès region, is located in northeastern Algeria at an elevation of 1058 me, 435 km southeast of the capital Algiers, and is one of Algeria’s five most important cities. Batna is also a highly vulnerable city due to the proliferation of dwellings that do not comply with seismic recommendations. Thus, it was classified as a low seismicity zone based solely on historical data from recent decades. Our work consists of analyzing and correlating historical and instrumental seismicity at the regional and local levels:the cataloged seismicity data for northeastern Algeria from 1856 to 2018 includes 3354 epicenters. To that end, our approach is based on three major axes: (a) seismic data analysis, (b) determination of seismic intensity attenuation for a target zone (the city of Batna), and (c) assessment of seismic hazardin terms of maximum expected intensity for a given return time. Using the distribution of GUMBEL Extreme Values (I and III), we were able to identify the reasonable maximum intensity limit for the city of Batna, which was estimated to be VII (MM) for a 100-year return period. This assessment provides critical support and a sound reference for the risk scenario to warn public authorities and citizens about the damages that may result from the occurrence of future earthquakes, allowing for the development of appropriate ORSEC plans and a strategy for managing and reducing seismic risk.