论文部分内容阅读
The Tianqiaogou-Huangyangchuan fault lies east of the main peak, Lenglongling Mount, in the east part of the Qilian Mountains and is one of the major active faults on the eastern section of the Qilian Mountains. The fault is separated into two segments at Guanjiatai village, the eastern and western segments, and has undergone obvious movement since the Holocene. Six trenches were excavated to study the paleoseismic activity along the fault. Integrated and comparative analysis of sediments in the trenches reveals 7 paleoseismic events and a historic earthquake on the fault since the Holocene. Their ages are: event Ⅰ is (10743±343)a BP, event Ⅱ (9038±39)a BP, event Ⅲ (7050±577)a BP, event Ⅳ (4847±185)a BP, event Ⅴ (3562±190)a BP, event Ⅵ (2476±194) a BP, and event Ⅶ (1505±253), respectively, and event Ⅷ is the 1927 Gulang M_S8.0 earthquake. It indicates that the fault might have contributed to the 1927 Gulang M_S8.0 earthquake. The temporal and spatial distribution of the paleoseismic events is relatively uniform and is characterized approximately by a quasi-periodic recurrence.
The Tianqiaogou-Huangyangchuan fault lies east of the main peak, Lenglongling Mount, in the east part of the Qilian Mountains and is one of the major active faults on the eastern section of the Qilian Mountains. The fault is separated into two segments at Guanjiatai village the eastern and western segments, and has undergone obvious movement since the Holocene. Six trenches were excavated to study the paleoseismic activity along the fault. Integrated and comparative analysis of sediments in the trenches reveals reveals 7 paleoseismic events and a historic earthquake on the fault since The Holocene. Their ages are: event Ⅰ is (10743 ± 343) a BP, event Ⅱ (9038 ± 39) a BP, event Ⅲ (7050 ± 577) a BP, event Ⅳ (3562 ± 190) a BP, event Ⅵ (2476 ± 194) a BP, and event Ⅶ (1505 ± 253), respectively, and event Ⅷ is the 1927 Gulang M_S8.0 earthquake. It indicates that the fault might have contributed to the 1927 Gulang M_S8.0 earthquake. The temporal and spatial distribution of the paleoseismic events is relatively uniform and is characterized by by a quasi-periodic recurrence.