Study of crustal thickness and Poisson ratio of the North China Craton
Study of crustal thickness and Poisson ratio of the North China Craton
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DOI：
10.3969/j.issn.0001-5733.2011.10.011
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发表时间：
2011-10
期刊：
影响因子：
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通讯作者：
Can Ge;Yong Zheng;X. Xiong
中科院分区：
文献类型：
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作者：
Can Ge;Yong Zheng;X. Xiong
华北克拉通（NCC）的地壳厚度和物理性质对于了解华北克拉通的破坏具有重要意义。我们从NCC地区部署的323个宽带地震台站收集了2007年8月至2009年3月发生的远震事件波形。为了获得可靠的接收功能，对震中距30°～95°范围内震级为M6的93次远震地震进行了宽带地震记录。 5 至 M8。收集了5个。基于这些数据，我们计算了每个地震台站的接收函数，并反演了具有精细空间覆盖的华北克拉通的地壳厚度和泊松比分布。地壳厚度和泊松比具有三个特征：（1）地壳减薄过程不仅发生在华北克拉通东部，而且还延伸到南北重力线。 (2)鄂尔多斯地块周边裂谷和盆地也出现地壳减薄现象,裂谷周边泊松比高于鄂尔多斯地块内部泊松比。有的裂谷泊松比高达0. 3。 (3) 华北克拉通地壳厚度与地形呈负相关，这与艾里地壳均衡相一致，这可能意味着华北克拉通地壳正在经历一个缓慢的破坏和地壳均衡过程。而华北克拉通中西部和东北部地壳均衡程度则较低。
The crustal thickness and physical properties of the North China Craton (NCC) are important for understanding the destruction of NCC. We collected waveforms of teleseismic events which occurred from August 2007 to March 2009 from 323 broadband seismic stations deployed in the NCC region. In order to obtain reliable receiver functions, the broadband seismograms of 93 teleseismic earthquakes occurred in the epicentral distance range from 30 degree to 95 degree with magnitudes M6. 5 to M8. 5 were collected. Based on these data, we calculated the receiver functions for each of the seismic stations, and inverted for the distributions of crustal thickness and Poisson ratio for the NCC with fine spatial coverage. There are three characteristics of the crustal thickness and the Poisson ratio: (1) Crustal thinning process not only occurs in the east part of NCC, but also extends to the North South Gravity Lineament. (2) Crustal thinning also occurs in the rifts and basins surrounding the Ordos block, and the Poisson ratio in the surrounding rifts is higher than that inside of the Ordos block. In some rifts the Poisson ratio is as high as 0. 3. (3) The crustal thickness of NCC is negatively correlated to the topography, which is in consistence with Airy isostasy, which may imply that the NCC crust is experiencing a slow process of destruction and isostasy. While the isostasy degree is much lower in the central west and north east part of NCC.