• 主题
高级搜索  >
历史搜索 清空历史
首页> 美国政府科技报告 >Regionalization of Crustal and Upper Mantle Q Structure in Eastern Eurasia Using Multiple Regional Waves
【24h】

Regionalization of Crustal and Upper Mantle Q Structure in Eastern Eurasia Using Multiple Regional Waves

机译：欧亚大陆东部地壳和上地幔Q构造的区域化多区域波

获取原文
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

We have mapped lateral variations in seismic Q in eastern Eurasia, including continental China, central Asia, Mongolia and Siberia, using high- frequency regional phases Lg and Pn, as well as long-period Rayleigh waves. We measured Q of crustal Lg waves in eastern Eurasia using two-station methods. Over 5,000 spectral ratios from 594 interstation paths were used to estimate Lg Q Omicron and Eta(Q at1 Hz and its frequency dependence). These path averages were used to derive tomographic models of Q Omicron and Eta with resolutions between 4 and 10 degrees. The Q Omicron model contains values that vary between 100 and 900. Q Omicron are the lowest in the Tibetan plateau, increase to moderate levels towards the east and north, and reach maxima in the Siberian and eastern Europe Cratons. Q Omicron values correlate well with regional tectonics. Most Eta values are between 0.14 and 0.50, with a mean of 0.18. These values are lower than those obtained previously. Pn spectra were collected from three seismic experiments in the Tibetan Plateau (TP) over four path groups to study Pn attenuation. A comparison of Pn spectra from these events reveal that mantle lid under north central TP attenuates Pn more severely than under central Asia. Over paths that sample either a mixture of northern and southern Tibet or eastern Tibet, Q Omicron and Eta are between about 250-270 and 0.0-0.1, respectively. Over the path group that samples easternmost TP the respective estimates are 374 +/- 51 and 0.3 +/- 0.1. Lateral variation of Pn attenuation inversely correlates with that of the Pn velocity. Possible causes of this variation include (1) a thermally driven mantle Q Rho, and (2) region-specific velocity structures. We utilized Rayleigh waves with periods longer than -15 s, derived from regional and near-teleseismic earthquakes, to map lateral variations in crustal and upper mantle shear velocity and attenuation across eastern Eurasia.

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号