伊朗活动构造发育特征

Characteristic features on Iranian Active Tectonics

伊朗是地震灾害频发的国家之一,有丰富的历史地震记载。按照构造特征与地震活动性的差异可将伊朗划分为6个地震构造区,包括北部的厄尔布尔士构造区、南部的扎格罗斯构造区和莫克兰构造区、中部的中伊朗块体构造区、大不里士构造区以及科佩特构造区,本文简要介绍了各构造区主要活动构造的基本特征和相应地震活动。受新生代阿拉伯板块与欧亚板块碰撞控制,伊朗地区处于挤压构造环境,活动构造以走滑和逆断-褶皱变形为主。根据活动构造特征和地震记录,伊朗地区的主要活动(断裂)构造具有发生7~7.5级地震的发震能力,莫克兰俯冲带具有发生≥8.0级地震的发震能力。伊朗北部主要城市德黑兰和大不里士面临着严峻的地震灾害风险,德黑兰北断裂带和大不里士断裂分别是威胁2个城市的主要活动断裂。伊朗的活动构造研究和防震减灾工作较为薄弱,可进一步加强历史地震与古地震研究、城市活动断层探测、活断层避让等工作。伊朗高原是研究青藏高原新生代演化的参照模型,中-伊两国都面临着长期的地震风险,两国之间有必要加强防震减灾国际合作,中国研究者可以更广泛地参与伊朗地区的活动构造研究。

Located in the Alpine-Himalaya seismic zone,Iran suffers from intense earthquake disasters,and there is a wealthy and diverse record of historical earthquakes which can go back for more than two thousand years witnessed by the Iranian civilization.On the basis of tectonic feature,geomorphology and seismicity,we divide Iran and adjacent areas into six tectonic provinces,namely Alborz seismic region in the north,Zagros region in the southwest,Central Iranian block region,Makran region in the southeast,Tabriz region in the northwest and Kopeh Dagh region in the northeast.Then,we briefly present the basic characteristics of major active tectonics in each seismic regions accompanied by main seismic activities.Dictated by the collision-subduction between Arabian plate and Eurasia plate in Cenozoic,Iranian active tectonics are feathered by widespread regional strike-slip and reverse faults which define a compressive kinematic regime.According to the nature of active tectonics and seismicity,major active tectonics in mainland Iran are capable of generating earthquakes with magnitudes of M_(W)7.0~7.5.Meanwhile,the Makran subduction zone could bear great earthquakes with magnitudes larger than M_(W)8.0.Cities in northern Iran,especially Tehran and Tabriz,are confronted with severe earthquake disaster risk.The Tehran North fault zone and Tabriz North fault are the major active faults that threaten Tehran and Tabriz,respectively.The current active tectonic research and earthquake disaster relief work in Iran is insufficient,thus it is strongly recommended that more efforts,such as paleo-seismological research,active fault survey and prospect in urban areas,active fault avoidance strategy,should be applied throughout the whole country.Iranian plateau,built during the continent collision between Eurasia plate and Arabia plate,can serve as a reference model of Tibetan Plateau,which will no doubt improve our knowledge on the Cenozoic tectonic evolutionary history of China's Mainland.China and Iran both face perpetual earthquake disaster risks,which calls for a more robust international cooperation in the field of protection against and mitigation of earthquake disasters.China could participate extensively in Iranian active tectonic researches and earthquake mitigation work.