Abstract: The Lixian Luojiapu fault zone shows clear activity since the late Pleistocene. The Holocene strata are directly offset in the Lixian-Luojiapu and Tianshuizhen-Jiezikou segments. Surface scarps are easily to be found and the gullies are sinistrally offset along the fault. Considering the widely distributed earthquake slope slides and liquifaction, it is suggested that the Lixian Luojiapu fault zone is the seismogenic structure of the 1654 Tianshui M8 earthquake. The average horizontal and vertical slip rates are 0.95mm/a and 0.35mm/a, respectively since late Pleistocene. The ratio of vertical slip rate to horizontal slip rate is about 1/3, which is about the same as the ratio between the vertical and horizontal displacement in an event.

Key words: Tibetan Plateau, Lixian Luojiapu fault zone, Earthquake of Tianshui

摘要： 礼县-罗家堡断裂带晚更新世以来有过明显活动。在礼县—罗家堡段和天水镇—街子口段直接错断全新世地层。断裂沿线地表陡坎发育,水系被左旋位错。结合沿该断裂带广泛分布的地震滑坡、砂土液化等,认为礼县-罗家堡断裂带是1654年天水南8级地震的发震构造。该断裂晚更新世以来的平均水平位错速率为0.95mm/a,平均垂直位移速率为0.35mm/a,垂直位移速率约为水平位移速率的1/3。这个比值与一次断裂突发性垂直位错量(1.9m)与水平位错量(5.2m)的比值基本吻合。

关键词: 青藏高原, 礼县-罗家堡断裂带, 天水地震