地震地质 ›› 1981, Vol. 3 ›› Issue (3): 47-60.

• 科研简报 • 上一篇    下一篇

中国大陆自由空气重力场的初步研究

魏梦华, 王启鸣, 史志宏, 殷秀华, 刘占坡, 张玉梅   

  1. 国家地震局地质研究所
  • 出版日期:1981-09-09 发布日期:2009-11-25

A PRELIMINARY STUDY OF THE FREE AIR GRAVITY FIELD IN CHINA CONTINENT

Wei Menghua, Wang Qiming, Shi Zhihong, Yin Xiuhua, Liu Zhanpo, Zhang Yumei   

  1. Institute of Geology, National Bureau of Seismology
  • Online:1981-09-09 Published:2009-11-25

摘要: 本文利用地面实测的重力资料计算并构制了从1°×1°到10°×10°平均的中国大陆自由空气重力异常图,并对这套图中所反映出来的基本事实进行了分析和解释,且就这些基本事实与大地构造、地壳均衡、地震活动的关系及其可能的地球动力学过程进行了讨论。

Abstract: On the basis of the measured ground data ten free air gravity maps of China have been constructed from mean free air values in square areas of 1白1? to 10白10? using average filter to eliminate successively the shorter wavelengths. These results indicate a great difference between East China and West China in the anomaly configuration: the anomaly value changes are gently in the East and sharply in the West: the short wavelength anomalies trend in a NE direction in the East and in NW in the West, whereas the long wavelength anomalies trend in a NS direction in the East and in EW in the West. In addition, there are four NW disturbance zones cutting across the NE linear anomalies in the East. From the map 1 (1白1?) can be seen that in the East there exist two prominent nearly parallel positive anomaly zones, one of which extends from the Changbaishan mountains through the Liaoning and Shandong peninsulas into the coastal ranges in the Zhejiang and Fujian provinces, and the other runs from the Dahin-gganling mountains along the Taihangshan mountains through the Qinling mountains into the ranges of western Hubei and Hunan provinces. Between the two zones exist a wide and low gravity anomaly zone associated with the Songliao, North China and Jianghan plains and Hengyang basin. In the West, the anomaly configurations are very complex and have the same NW direction as the positive linear anomalies over the Qilianshan mountains, the eastern Tianshan and the Altayshan. On the map 2 (3白3?) are shown the high-amplitude positive anomalies for almost all the mountain regions and the low-amplitude positive or negative anomalies for all the plains and plateaus, whereas the interior basins always correspond to the large high-amplitude negative anomalies. On the map 3 (5白5?) can be found five dominant large anomalies for the China continent: the positive from 110癊 to the east, the negative over the Sichuan basin and Ordos plateau, the positive over the Qinghai and Xizang region, the negative over the Neimon-ggol and Xinjiang Autonomous regions. Besides, a great negative anomaly appears in the eastern Xizang. As shown on the maps 4 and 5 (7白7? and 9白 9?), the direction of the main linear anomalies turns into a normal NS one in East China and EW in the West. It is suggested that the short wavelength anomalies (1白1?) associated with the tectonic features are produced due to successive tectonic movements causing the non-homogenous mass distribution in the lithosphere. The moderate wavelength anomalies (3白3? and 5白5?) resulted from the broad bent of the lithosphere caused by the current stress from plate motions. Probably, the long-wavelength anomalies (7白7? and 9白9?) are related to the mantle deep-seated mass inhomogeneity, except the effect of the plate motions. The relation of the above-stated phenomena to the tectonic framework, isostasy, seismicity as well as the possible geodynamical process are also discussed.