闽粤台琼海岸大震构造的定量标志——兼论定性标志

THE QUANTITATIVE TECTONIC INDICATORS OF COASTAL GREAT EARTHQUAKES IN FUJIAN , GUANGDONG, TAIWAN AND HAINAN ——With a Discussion of the Qualitative Indicators

本文论述闽粤台琼海岸大震区的莫霍面隆起幅度、第四纪抬升幅度和晚全新世海岸抬升幅度为主的大震构造的定量标志,以及某些定性标志。另外,对地表隆起带的定量标志研究方法作了简要地叙述。我国台湾是世界著名的新构造带和大震区.福建、广东和海南各有一个海岸大震区。这些大震区海岸必然遗留下许多地壳活动的遗迹。其中海岸活动遗迹,由于海平面作标志面,则可确定某一个时期的海岸升降幅度,甚至正反向的升降周期和升降速率。

This paper expounds the quantitative tectonic indicators of great earthquakes. The main quantitative indicators are the uplift amplitudes of the Moho, Quaternary and the Late Holocene coast. Taiwan is a famous neotectonic zone and great earthquake area. Fujian, Guangdong and Hainan have only one coastal great earthquake area each. Along the coast of great earthquake there are certainly many remains of crustal activity. Among them remains of the coastal activity can determine the amplitude of coast sinking and elevation in a certain period. even the positive and negative sinking and elevation cycle and rate, because the sea level is an accurate marker horizon. Over the part two or three thousands years the main markers of sinking -elevation have been the high beachrock in the great earthquake areas of Fujian, Guangdong and Hainan. Up to now the high beachrocks discovered in the great earthquake areas of Fujian. Guangdong and Hainan respectively have been the first finds in China and abroad. Both high beachrocks and great earthquake areas coincide with the uplift and fault throw of the Moho. High beachrock is the direct quantitative marker of the great earthquake area and structure.In nine great earthquake areas with magnitude over 7 along the coasts of Fujian. Guangdong. Taiwan and Hainan. Holocene marine sediments on the surface are all uplifted more than 20 m, and the Moho is uplifted about 3 km. The authors have discovered the inner link among Holocene high -level littoral sediments, great earthquake areas, and strong uplift areas of the Moho. So long as one knows one of the first two factors, one can deduce the other two tectonic factors of great earthquakes, the accuracy being 100%.