关键词: 活动断裂, 火山喷发, 龙海—漳浦沿海

Abstract: Longhai—Zhangpu coastal region lies in the so-called Golden Triangle area of southern Fujian Province. Tectonically,it is located on the southern segment of the Changle-Zhaoan fault zone,being one of the regions of Tertiary and Quaternary basaltic eruptions in southeast coastal area of China. In this area there exist the Longhai Liuhui-Zhangpu Jiangjun'ao and Longhai Gangwei-Zhangpu Huxi faults,along which occurred basaltic eruption. The faults have been significantly active since Quaternary,and several small to moderate earthquakes occurred on the faults. In this paper,the basic characteristics of late Quaternary activities and the combination relation of the faults are discussed on the basis of the analysis of along-fault basaltic eruption during late Tertiary to late Pleistocene,as well as the differential variation of geomorphic surfaces and marine deposits on both sides of the faults. The results show that the Longhai Liuhui-Zhangpu Jiangjun'ao fault is a late Pleistocene active fault. During late Tertiary to late Pleistocene,three periods of basaltic eruptions had occurred along the fault,among which the first period occurred in Pliocene to early Pleistocene,the second period in middle Pleistocene and the third period in late Pleistocene. The Longhai Gangwei-Zhangpu Huxi fault can also be assigned to late Pleistocene active fault. The elevation rate of the downthrown side of the fault is estimated to be 1.11 mm/yr. These two faults have dissected the area into the Gangwei graben,south Taiwushan horst and the graben in the sea area to the east of Liuhui-Jiangjun'ao.

Key words: active fault, volcanic eruption, Longhai-Zhangpu coastal area