西藏当雄6.6级地震与尼木6.5级地震震害特征分析

Damage Analysis of Dangxiong M_s6.6 and Nimu M_s 6.5 Earthquakes in Tibet

2008年10月6日16时30分在西藏拉萨市当雄县(北纬29°48′,东经90°21′)发生了MS6.6级地震,而在1992年7月30日16时24分在拉萨市尼木县(北纬29°35′,东经90°15′)曾发生过MS6.5级地震。上述2次地震发生在同一活动构造带上,地震类型相同,震级、震源深度也相差不大,但2次地震造成的灾害损失却相差很大。作者在地震现场调查的基础上,对比分析了这2次地震的人员伤亡和震害情况,探讨了造成地震灾害损失轻重的主要因素。

There occurred two earthquakes in Tibet in recent years, in which one was at 04：30 p.m. on October 6, 2008 in Dangxioan county of Lhasa city （north latitude 29°48′, east longitude 90°21′） with magnitude 6.6; and the second was at 04：24 p.m. on July 30, 1992 in Nimu county of Lhasa city （north latitude 29°35′, east longitude 90°15′） with magnitude 6.5. Although these two earthquakes belong to the same tectonic unit, and share many similarities in seismic type, magnitude and depth of epicenter the corresponding damage is quite different. Based on the field investigation, we perform a comparison study of the life loss and building damage cased by these two earthquakes. Finally, the possible cause of such different damage is discussed.