范家坝-临江断裂活动与1879年甘肃武都南8级地震的讨论  

DISCUSSION ON THE ACTIVITY OF FANJIABA-LINJIANG FAULT AND THE SOUTH WUDU, GANSU PROVINCE M 8 EARTHQUAKE OF 1879

作　　者：冯希杰[1] 董星宏[1] 刘春[1] 李晋[1] 

机构地区：[1]陕西省地震局,西安710068

出　　处：《地震地质》2005年第1期155-163,共9页Seismology and Geology

摘　　要：1879年甘肃武都南 8级地震发震断裂的确认是一个未决的问题。文中通过卫星影像解译、史料记载分析,认为沿文县东北水坑山北麓NEE向的范家坝 -临江断裂可能分布有该次地震的地表破裂带,因而,这一条断裂可能是该次地震的发震断裂。由此,可在发震断裂的产状变化、活动方式、地表破裂带长度、水平位错量大小及沿断裂的分布、断裂的区域归属、宏观震中位置、可能震级大小、震害分布等诸多方面取得一致。The earthquake occurred in Jiezhou, Gansu Province on July 1, 1879 (May 12, Guangxu 5, Qing Dynasty) is one of the largest earthquake events in Chinese history. The effect of this event spread over more than ten provinces. According to historical data, the magnitude of this earthquake has been estimated to be 8 or 71/2, and the macroscopic epicenter has been located at Mianshanheba (104.7E, 33.2N), south of Wudu, Gansu Province, with type II precision of estimation (≤25km error). As the earthquake occurred in the areas of high mountain ridges difficult to be approached, it has not been studied in detail so far. It is one of the 3 M=8 earthquakes in China that their relation to active faults had not been revealed so far. Recently, we have found that in satellite images a NNE-trending lineament can be clearly observed along the northern foot of the Shuikeng Mountains to the northeast of Wenxian County, Gansu Province. It extends eastward from Shifang Village to the northwest of Wenxian County, passing through Liangjiaba, Malian River, Fanjiaba, Miaobeihou, Guanjiagou, Jianzuishan Mountains, Shuikengya, northern slope of the Fangmashan Mountains, Songjia Mountains and Shenjiana'an, and then gradually becomes unclear after crossing through the Bailongjiang River and turning northward at 500m downstream from the Majiaba. The lineament has a total length of about 30km, among which about 21km can be identified to be surface fracture zone (from the bank of the Bailongjiang River to the top of the western hills of Guanjiagou). The lineament offsets left-laterally a series of ridges and gullies. In comparison with geologic data of this region, this lineament image coincides well with the NEE-trending Fanjiaba-Linjiang Fault. The interpretation of satellite images for the whole region and re-collation of historical records about this earthquake have confirmed that the Fanjiaba-Linjiang Fault bears a close relation to the southern Wudu earthquake, and is most probably the causative fault of this earthquake. This study,

关 键 词：8级地震 发震断裂 地表破裂带 断裂活动 宏观震中 震害分布 产状 史料记载 大小 水平 

分 类 号：P315[天文地球—地震学] P316.313[天文地球—固体地球物理学]