东亚北部地区现代板块构造的运动学分析

从原欧亚板块划出阿穆利亚微板块，并建立一个包括太平洋、北美、欧亚、鄂霍次克及菲律宾海等板块在内的６板块系统，利用地震滑移矢量，转换断层走向，洋中脊扩展速率，以及最新的ＧＰＳ观测资料，采用Ｍｏｎｔｅ－Ｃａｒｌｏ盒子法，反演得到该６板块系统的欧拉运动矢量．本文得到的有关欧拉矢量为：ＡＭ-ＥＵ（６０．４２°Ｎ，１２３．２５°Ｅ，０．０２５°／Ｍａ），ＡＭ-ＯＫ（５３．２０°Ｎ，１４１．９５°Ｅ，０．４７６°／Ｍａ）以及ＡＭ-ＰＨ（５０．８４°Ｎ，１５８.１３°Ｅ，１.２０４°／Ｍａ），ＡＭ－ＥＵ的欧拉运动极点位于贝加尔隆起的东北及斯塔诺夫山脉的西北，并给出在贝加尔隆起有０．４－０．７ｍｍ／ａ的扩张，与从地质学证据得到的估计结果一致；由ＡＭ－ＯＫ及ＡＭ－ＰＨ欧拉运动矢量可以分别得到日本海东缘的６-１５ｍｍ／ａ及日本南海地槽带的５１－６６ｍｍ／ａ收敛速率，与最新的ＧＰＳ观测结果并不一致．因此，东亚北部地区存在独立的南中国微板块及其它亚尺度的微板块，可以更好地描述该地区现今板块构造的运动规律．

KINEMATIC ANALYSIS OF MODERN PLATE TECTONICS IN NORTHEASTERN ASIA

The Amurian microplate can be discriminated from the Eurasian plate.We thus set up a 6-plate system including Pacific, North American, Eurasian,Philippine Sea, Okhotsk and Amurian plates. By means of the earthquake slip vectors,transform fault azimuths, spreading rates and the latest GPS data, we get the Eulervectors describing motions of this 6-plate system by using the Monte-Carlo Boxmethod. Some Euler vectors obtained in this study are: AM-EU （60.42°N, 123.25°E,0.025°/ Ma）, AM--OK （53.20°N, 141.95°E, 0. 476°/ Ma）, and AM-PH （50.84°N,158.13°E, 1.204°/ Ma）. The AM-EU pole is located to northeast of the Baikal Riftand to the northwest of the Stanovoy Range. The results of this study imply that theBaikal Rift is extending at a rate of 0.4-0.7mm / a, which are consistent with thegeologically estimated rates. The AM-OK and AM-PH Euler vectors show 6-15mm/a of convergence rate in the eastern margin of the Japan Sea and 51-66mm/ a ofconvergence rate along the Nankai Trough, respectively, which are not consistent withthe latest observed GPS data. An independent South China microplate or othermicroplates, which are discriminated from the Eurasian plate, are accordingly helpfulin describing the current plate motions of the Northeastern Asia.