Crustal thickness variation in south-central Alaska
Crustal thickness variation in south-central Alaska
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DOI：
10.1130/g22615.1
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发表时间：
2006-09
期刊：
影响因子：
5.8
通讯作者：
E. Veenstra;D. Christensen;G. Abers;A. Ferris
中科院分区：
文献类型：
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作者：
E. Veenstra;D. Christensen;G. Abers;A. Ferris
通过对阿拉斯加山脉宽带实验(BEAAR)期间记录的宽带远震波形的接收器函数分析，确定了地壳厚度。北部低地之下的典型地壳厚度为26公里，而山脉下面的地壳厚度为35-45公里。从厚地壳到薄地壳的转变与Hines Creek断层的位置相吻合，Hines Creek断层是主要的构造地层边界。由接收函数确定的地壳厚度与假设艾里型均衡的地形预测的地壳厚度一致，表明阿拉斯加山脉受到其地壳根的补偿。然而，在山脉以北，地壳系统地比简单的艾里均衡所预测的要薄。横跨Hines Creek断层的地壳密度差为4.6%，北部为2700 kg m−3，南部为2830 kg m−3，这解释了简单艾里均衡预测的地壳厚度与接收函数分析确定的地壳厚度之间的观测差异。
Crustal thicknesses have been determined by receiver function analysis of broadband teleseismic waveforms recorded during the Broadband Experiment Across the Alaska Range (BEAAR). Typical crust beneath the northern lowlands is 26 km thick, while beneath the mountains it is 35–45 km thick. The transition from thick to thin crust coincides with the location of the Hines Creek fault, a major tectonostratigraphic boundary. Crustal thicknesses determined by receiver functions agree with those predicted from topography assuming Airy type isostasy, suggesting that the Alaska Range is compensated by its crustal root. North of the range, however, the crust is systematically thinner than predicted by simple Airy isostasy. A crustal density contrast of 4.6% across the Hines Creek fault, 2700 kg m−3 to the north and 2830 kg m−3 to the south, explains the observed difference between the crustal thicknesses predicted by simple Airy isostasy, and the crustal thicknesses determined by receiver function analysis.