Rapid Earthquake Loss Estimation Model for Algerian Urban Heritage: Case of Blida City

ABSTRACT

The present work develops an integrated rapid loss assessment model aiming to quickly estimate the expected damages and their spatial distribution for the Algerian urban heritage context. It predicts the expected damages for a given earthquake scenario, i.e. an historic event or a reference scenario. Furthermore, in the immediate aftermath of an earthquake, the model updates the damages according to the seismic signals either recorded in the zone of interest or derived quickly from the GMPE (Ground Motion Prediction Equations). It combines a seismic damage assessment approach developed for existing building in Algeria and a GIS system, in order to automatically generate relevant damage maps for decision-making and rescue purposes. It is implemented and run for a real case of Blida city, located in the central northern part of Algeria, which is a highly dense urban area (3070 inhabitants/km²) containing an important architectural and historical heritage.

For calibration purposes, the model is implemented and run in order to generate the seismic damage GIS maps for a set of 23,000 buildings, for a potential earthquake Mw = 7, consistent with the area seismicity.

The results show that serious damages and complete destruction are expected in particular areas, mainly the oldest districts with an urban heritage consisting of old unreinforced masonry buildings dating from the XVI to the middle of the XX centuries. Less important damages are expected for newly erected constructions built during and after the last half of the XX century, as they meet the structural design standards and built on adequate soils.

KEYWORDS:

• Algerian urban heritage
• Blida city
• disaster decision making
• GIS risk maps
• loss assessment
• risk mitigation

Acknowledgments

The present work has received the financial support of the National Earthquake Engineering Research Center (CGS). The authors are very grateful to the local authorities of Blida for the data acquisition and easy access to administrations and building inventory site. Authors would like to thank also their colleagues Professor Nasser Laouami, Drs. Abdenacer Slimani, Mounir Ait Belkacem, Nacim Yousfi, Nabila Guessoum and Dalila Ait Benamar for their cooperation and support.

Disclosure statement

No potential conflict of interest was reported by the author(s).