Liu Ruihua, Zhang Zhongying
1989, 9(2): 174-182.
The neotectonic movement of Hainan Island has been being rather active since the late Tertiary period.On the basis of the old geological structures,the movement greatly affects the modern landform and the quaternary sediment in Hainan.The characteristics of the movement are as follows:(1)Three groups of main faults,the east-west,north-west and north-east ones,dominate the whole island and form a series of faultblock and neotectonic zones.There are relatively thicker stratum of pliacene series and the Quaternary system deposit in the downwarping area,and in upwarping area the bedrock appears or only thin sedimentary stratum of the Quaternary are on it.(2)The volcanos frequently erupted along the three groups of faults or at the crossford of the faults.The eruptions are of periodic,continual,intermittent and transferable.(3)The earthquakes,closely related to the geological structures,are active and strong,especially in the North and East of the island.(4)The movement of the coast is obviously different in different parts where the East coast is uplifting while the West one is subsiding and the mountains in the middle of the island is mainly rising slowly and intermittently.(5)The modern river valleys mostly develop along the faults.