【摘要】 2008年5月12日四川汶川发生MS8.0大地震,形成了200多km长的地震地表破裂带。破裂带的古地震研究对于认识龙门山断裂带的活动习性和大地震的发生规律具有重要的理论和现实意义。文中用光释光(OSL)测年中的校正感量简单多片再生法(SMAR),对映秀-北川地震地表破裂带擂鼓探槽样品进行了光释光测年,并对探槽中含有的炭屑进行了AMS14C测年。样品的光释光年龄和校正的AMS14C年龄吻合,该地区与汶川地震类似规模的上一次古地震事件发生在距今约(2.1±0.2)ka至(1.1±0.2)ka间。更多还原

【Abstract】 Paleoseismic studies conducted along the surface rupture of the Wenchuan earthquake(MS 8.0)of 12th May 2008 provide important information regarding earthquake reoccurrence intervals and slip rates of the Longmen Shan Fault zone.The Leigu trench was excavated along the middle segment of the surface rupture of the Yingxiu-Beichuan Fault zone.Based on the syntectonic sedimentary structure,two earthquake events,including the Wenchuan event,were identified at this site.This study utilizes Optically Stimulated Luminescence(OSL)dating of samples collected from the Leigu trench section,using SMAR(Sensitivity-corrected Multiple Aliquot Regenerative-dose)protocols.AMS14 C dating was also carried out on charcoal from the same sediments.OSL ages are generally consistent with the calibrated AMS14 C ages(cal a BP)for the same units.The penultimate earthquake event similar to Wenchuan earthquake scale in this region occurred(2.1±0.2)ka to(1.1±0.2)ka.更多还原