IAEG2006 Paper number 305 © The Geological Society of London 2006 1 Evaluation of seismic sources for hazard assessment in the Fujairah Emirate (UAE) FARSHAD JAMALI 1 , S. M. FATEMI AGHDA 2 & ALIREZA ALIYARI 3 1 NDRII. (e-mail: f.jamali@gmail.com) 2 NDRII. (e-mail: fatemi@ndrii.com) 3 NDRII. (e-mail: araliari@gmail.com) Abstract: The Arabian Peninsula is separated from Africa by the Red Sea and from Iran by the Persian Gulf and the Oman Sea, and is bounded on the south by the Arabian Sea and the Gulf of Aden. Geologically, it consists of crystalline Precambrian basement overlain by low-dipping Phanerozoic sedimentary and volcanic rocks, and originated 25-30 million years ago as a consequence of rifting along the line of the eventual Red Sea and Gulf of Aden. At the present time, the northern part of the Arabian plate moves northwest, with respect to the Eurasian plate, at a rate of 20±3 mm/yr. The United Arab Emirates is a part of Arabian Peninsula and lies at its northeastern part. Fujairah and the area under study is located in Northeastern Emirates. Based on geological data, mountains in the west of Fujairah consist of ophiolites. These ophiolites continue towards the south and southeast along the seashore with Quaternary deposits in the east. The seismicity of the studied area, in particular, has received little attention. Considering its location on the southeastern part of the Arabian plate and the geological, tectonic and the limited seismicity information, the presence of a relatively low-to-moderate seismic hazard in this region is quite evident. The major earthquake sources around the studied area are represented by the regional faults of the plate boundary. These occur at variable distances from the region. Other secondary earthquake sources are represented by the local crustal faults that cross the region in specific directions, mainly NE, NW, and N-S. In recent years, earthquakes have struck the region resulting in some damage. In the paper the authors have tried to evaluate the seismic hazard in Fujairah Emirate which is essential for further study in order to carry out appropriate urban planning. Résumé: La Péninsule Arabique se sépare de l’Afrique par la Mer Rouge et de l’Iran par le Golfe Persique et la Mer d’Oman. Elle est limitée au sud par la Mer Arabique et le Golfe d’Aden. Au contexte géologique, elle consiste en un socle Précambrien couvert par les roches sédimentaires et volcaniques du Phanérozoïque. Cette péninsule est formée, il y 25-30 Ma, en conséquence d’un rifting le long d’une trace qui a conduit à la formation de la Mer Rouge et du Golfe d’Aden. Actuellement, la partie septentrionale de la plaque d’Arabie se déplace vers le NW par rapport à la plaque d’Eurasie à une vitesse de 20±3 mm/an. Les Emirats Arabes Unis forment une partie de la péninsule Arabique et se posent à sa partie NE. Fujaïrah et la région sou cette étude se trouvent dans le NE des Emirats. La sismicité de cette région n’est pas bien étudiée. En considérant la position de cette région sur la partie SE de la plaque d’Arabie et en liant sur les renseignements géologiques, tectoniques et sismologiques, on pourrait parler d’un risque sismique d’un niveau faible ou modéré. Les sources majeures de la sismicité dans la région sont les failles régionales constituant la bordure de la plaque d’Arabie. Les événements sismiques surviennent dans des distances variables de la région Un deuxième group des sources de la sismicité est représenté par les failles régionales dans la croûte traversant la région dans des directions particulières, notamment NE, NW et N-S. Dans ces dernières années, les tremblements de terre ont touché la région et abouti aux dégâts considérables. Dans ce papier, les auteurs ont tenté d’évaluer les aléas sismiques à l’Emirat de Fujaïrah. Cette évaluation serrait essentielle pour les études du futur pour exécuter un planning urbain satisfaisant. Keywords: earthquakes, seismic risk INTRODUCTION Since its creation, the Arabian plate moved northeast away from Egypt and Sudan, north away from Somalia, and rotated counter clockwise about a point in the vicinity of the Gulf of Suez. Such movement is accommodated by compression and strike-slip faulting along the Bitlis and Zagros zones, where the Arabian plate collides with and subducts beneath the Eurasian plate, and by strike-slip displacement along the Dead Sea transform. Arabian Peninsula is limited by four major tectonic features, largely of post-Cretaceous age. The Red sea and Dead sea rift system at the west and northwest. The thrust zone from the Alpine orogeny at the north. The mobile belt of Zagros and Oman mountains at the east and southeast. The wrench fault associated with Owen fracture zone at the south. At the present time, the northern part of the Arabian plate moves northwest, with respect to the Eurasian plate, at a rate of 20±3 mm/yr. Because of extension regions, the southern, southwestern, and southeastern margins of the Arabian plate have weak to moderate earthquake activity. The compressive northerly and northeasterly margins, conversely, are regions of strong earthquake activity.