First Arab Conference on Disaster Risk Reduction Aqaba (Jordan), 19-21 March 2013 Urban Seismic Risk in North African Countries Djillali BENOUAR University of Science and Technology Houari Boumediene (USTHB), Algeria INTRODUCTION North African countries are growing increasingly dependent on new products and services that make up our domestic critical infrastructure network. Several factors contribute to region’s vulnerability to the numerous varieties of threats. First the region’s population, built environment, and wealth, are increasingly concentrated in a small number of highly vulnerable cities and many such communities are at risk from multiple hazards. The rapid urbanization, development of critical engineering works such as dams, decaying building stock, implementation of various industries within and around the main cities. INTRODUCTION (Cont’d) • Many recent disasters in the last decades had their main impact in urban areas where there is a large concentration of people with a heavy dependency on infrastructure and services. • Industrialization of CITIES with modern types of buildings and the large concentration of populations, with a heavy dependency on infrastructure and services, living in large cities and/or settling in hazardous areas are matters of growing concern, as they contribute to heavier loss of life and seriously increasing the economic losses in future disaster damage. Major seismic fault lines and urban vulnerability Seismicity of the Arab Region Greatest Earthquakes in the Maghreb Region Convergence direction and rate (Argus et al., 1989) 6.7 4.5 3.9 5.3 6.0 3.7 4.5 4.1 2.8 2.9 3.1 3.6 Boumerdes (Algeria) earthquake 2003 Main fault lines around Algiers Khair al Din Fault Zemmouri Fault Thenia Fault Chenoua Fault Sahel Fault Blida Fault Morocco Sesimicity during 1993-2005 More than 3500 seismic events Main fault lines in Tunisia Corti, G. et al (2009) Coexisting geodynamic processes in the Sicily Channel. Geological Society of America Special Paper 409, p. 83–96, Libya seismicity during 1907-2009 Egypt seismicity during 1900–2004. Black lines are surface faults North African seismogenic zones (NAGET, Submitted for publication) Maximum Computed Design Ground Acceleration (DGA) Distribution Map (NAGET, Submitted for publication) Seismic Hazard Map of the Maghreb Region 38 PGA (g) 36 34 0.5 32 0.4 30 0.3 28 0.2 26 0.1 24 (Benouar et al. 1996) 22 0.0 20 -10 -8 -6 -4 -2 0 2 4 6 8 10 12 Fig 16:Iso-acceleration map of the Maghreb region for a lifetime of 50 years with an exceeding probability of 10 % using Ambraseys (1995) horizontal PGA attenuation law TSUNAMI RISKS: Example of mapping of source zones in the Mediterranee. Major Tsunamis along North Africa Data: Transfer catalogue, Soloviev et al., 2000; Tinti et al., 2001; ITC2004; Marinas-Salord, 1990; Harbi et al., 2003, 2007, Alasset et al., 2006 Dellys Lajenna before the earthquake Dellys Lajenna after the 2003 earthquake Past major urban earthquakes/seismic disasters and their impact upon urban areas The main damaging earthquakes of: 1960 Agadir (Morocco), Mw 5.7, 15000 victims 1980 El Asnam (Algeria), Mw 7.3, 3000 victims 1992 Cairo (Egypt) , Mw 5.8, 541 victims 2003 Boumerdes (Algeria), Mw 6.8, 2278 victims 2004 Al Hoceima (Morocco), Mw 6.4, 628 victims BEHAVIOUR OF HOSPITALS DURING THE 1980 EL ASNAM (ALGERIA) 7.2 EARTHQUAKE Hospital before the Hospital after the 1980 El 1980 El Asnam Asnam (Algeria) 7.2 (Algeria) 7.2 Earthquake Earthquake BEHAVIOUR OF HOSPITALS DURING THE 1980 EL ASNAM (ALGERIA) 7.2 EARTHQUAKE THE 2003 BOUMERDES (ALGERIA) 6.8 EARTHQUAKE 2278 dead 11450 injured 45 missing 182 000 homeless 19 000 houses destroyed 128 000 seriously damaged 5 B.USD direct losses Pancake collapse of buildings Bâtiments construits avant le code parasismique (poteaux faibles) Bâtiments construits avant le code parasismique (poteaux faibles) Bâtiments construits avant le code parasismique (barres d’acier lisses) Etage souple + scellement Etage souple Etage souple Bâtiment Sous dimensionné (Corso) Bâtiment Sous dimensionné (Corso) Bâtiment Sous dimensionné avec Rdc souple(Tidjelabine ) THE 1960 AGADIR (MOROCCO) 5.7 EARTHQUAKE Dead: 15 000 Buildings destroyed: 3650 Injured: 4 000 Buildings repaired: 250 Homeless: 20 000 SCOPE OF DAMAGE BY ZONE KASBAH 100% YACHECH 100% FOUNTI 95% TALBORDJ 90% PLATEAU ADMINISTRATIF 70% VILLE NOUVELLE 60% FRONT DE MER 60% QUARTIER INDUSTRIEL 30% ANZA 5% PORT 5% Main Past earthquakes in Morrocco Morocco: Agadir Earthquake February 29, 1960 (M5.7) THE 2004 AL HOCEIMA (MOROCCO) 6.4 EARTHQUAKE Dead : 628 Injured : 929 Homeless: 15320 Buildings Collapsed: 2539 in which 2498 in rural areas and 41 in urban zones • MAJOR DRIVERS OF VULNERABILITY IN URBAN AREAS Vulnerability of the Urban System • Critical infrastructures in main cities are made up of the following sectors: energy and utilities (electrical power, natural gas and oil transmission systems), communications (telecommunications and broadcasting systems); services (financial services, food distribution and health care); transportation (air, rail, marine and surface); safety (emergency services) and government services (major government facilities and information networks). Social vulnerability (Cutter 2003) • Social vulnerability is described using - The individual characteristics of people (age, race, health, income, type of dwelling unit, employment, education) -The characteristics of communities and the built environment, such as the level of urbanization, growth rates, and economic vitality, that contribute to the social vulnerability of places. Social vulnerability • Insufficient resources for DRR • unplanned urbanization, • Settlements within high risk zones, • lack of compliance to building codes , • deficient urban management practices, • Unpreparedness to confront disasters • Poor quality of workmanship (lack of training) Physical vulnerability 1- Soft story, 2- Traditional masonry bearing walls not linked to each other (rural and urban) 3- Short Columns 4- Structural asymmetries (in elevation but mainly in plane): discontinuities in mass, stiffness, resistance, et ductility generate torsion and stress concentration often unbearable 5- Heavy roofs and floors with relative stiffness « beams-columns » too unbalanced (Weak columns) Physical vulnerability 6- Insufficient width of seismic joints 7- Heavy decorative elements poorly hung to facades 8- Too important cantilever beams 9- Huge stock of vulnerable buildings exists today in most Arab cities Physical vulnerability • Errors in design: Lack of seismic design: structures built before the seismic code (Algeria 1981), self constructions (60% of total constructions) • Soil dynamics, site effects, liquefaction, landslides, etc. • Poor quality of workmanship and materials , Low resistance of concrete (14 à 17 MPA) • substandard construction and callous contractors and builders Physical vulnerability • deficiencies in the monitoring and control of constructions • Lack or insufficient maintenance of buildings • lack of building safety enforcement, lack of land use planning, • lack of design, inspection, plan review, and material quality , and lack of insurance Seismic vulnerability Seismic vulnerability reduction should not taken only as a technical problem but also a political, legal and socio- economic problem which needs a holistic approach beyond regulationS Some analysis of the existing risk reduction practice in urban areas, • PROVIDING DRR EDUCATION IN SCHOOLS AND COMMUNITIES • Review of the Algerian seismic building Code 1999/version 2003 • Establishment of the Algerian Seismic Public Works Code (RPOA 2010) DRR implemented actions SEISMIC HAZARDS MAPS AT NATIONAL AND REGIONAL LEVELS (ISO-ACCELERATIONS MAPS) AND EVALUATION AT SITE LEVEL SEISMIC MICROZONING MAPS (MORE THAN 40 CITIES IN ALGERIA) SITE EFFECTS STUDIES SEISMIC VULNERABILITY ASSESSMENT (STRATEGIC BUILDINGS IN LARGE CITIES IN ALGERIA. EARTHQUAKE DISASTER SCENARII (ALGERIA: FOR THE CITIES OF ALGIERS AND BLIDA INSURANCE SCHEME (ALGERIA IMPLEMENTED SINCE 2004) Site effects evaluation for the Algiers Microzoning for most important wilayas Achieved . Chlef . Alger . Mascara On going . Boumerdes . Blida . Tipaza . Constantine Perrcentage of damage for intensity VIII 1 Alger Centre 2 Sidi Mohamed 3 El Madania 4 Hamma Annassers 5 Bab el Oued 6 Bologhine 7 Casbah 8 Oued Korich 9 Bir Mourad Raïs 10 El Biar 11 Bouzareah 12 Birkhadem 13 El Harrach 14 Oued Smar 15 Bourouba 16 Hussein Dey 17 Kouba 18 Badjarah 19 Bab Ezzouar 20 Ben Aknoun 21 Raïs Hamidou 22 Djasr Kasentina 23 El Mouradia 24 Hydra 25 Mohammadia 26 El Magharia Earthquake scenario for Algiers • Findings • Human losses : 3081 dead 40917 injured • Over a population of 1 499 000 Habitants • Economic losses : 56 Billions DZD • GAPS AND CHALLENGES GAPS AND CHALLENGES • LACK OF ADEQUATE INTERSECTORIAL COORDINATION OF DRR • INSUFFICIENT IN PUBLIC EDUCATION • LACK OF AWARENESS AMONG SEVERAL STAKEHOLDERS • MANDATORY ZONING, SITE EFFECTS AND LAND USE BASED ON HAZARDS • RETHINK EARLY WARNING SYSTEMS. GAPS AND CHALLENGES • MOST ACTIVITIES ARE CONDUCTED TOWARDS RESPONSE RATHER PREVENTION • BUILD RESILIENCE TO COMMUNITIES AND SOCIETIES • BUILD A CULTURE OF RISK • IMPLEMENT HFA • IMPLEMENT INSURANCE SCHEME TO COVER DAMAGE FROM DISASTERS • GOOD GOVERNANCE • ACCOUNTABILITY AND TRANSPARENCY ﺷﻛﺭﺍ THANK YOU Email: [email protected] .