North China sub-craton lithospheric structure elucidated through coal mine blasting |
| |
Authors: | Zhao JinRen Zhang XianKang Wang FuYun Zhang ChengKe Zhang JianShi Liu BaoFeng Pan SuZhen |
| |
Institution: | (1) Geophysical Exploration Center, China Earthquake Administration, Zhengzhou, 450002, China |
| |
Abstract: | We present a super-range seismic observation along the >1300-km-long profile passing through the Yinchuan basin and the Ordos
block from the blasting point towards the southeast triggered by a large-(dynamite) scale coal blast in the Ningxia Hui Autonomous
Region’s Helan Mountain (yielded a profile). The seismic wave information from the uppermost mantle reflecting different depths
was obtained by the China continental seismic survey. Pn refracted waves from the uppermost mantle were effectively traced
up to 500 km and beyond. The stable dynamic and kinematic characteristics of the Pn wavegroup indicate that the uppermost
mantle below the Ordos block is a gently changing structure with a weak positive gradient. If Pm1, Pm2 waves are considered
as the wave groups from the upper mantle, there may be distinct structural strata in the upper-mantle structures with average
velocities of 7.70–7.80 km/s and 8.10–8.20 km/s, respectively. Based on the travel-time curve feature of Pm1, Pm2 waves, there
may be a certain layer with a reverse velocity between the M1 and M2 interfaces. The depth range indicated by them is about
110–120 km and 200–220 km. These phenomena basically reflect the structural features of the upper-mantle lithosphere in this
region. The information obtained may provide meaningful references for surveying North China craton lithospheric structures,
as well as understanding the shapes and structures of different spherical layers within the upper-mantle.
Supported by National Natural Science Foundation of China (Grant No. 90814012) and National Basic Research Program of China
(Grant No. 2004CB428400) Contribution No.: 0801, Geophysical Exploration Center, China Earthquake Administration |
| |
Keywords: | large mine blasting observation of super-range seismic profile upper-mantle waves lithospheric structure |
本文献已被 CNKI SpringerLink 等数据库收录! |
| 点击此处可从《中国科学通报(英文版)》浏览原始摘要信息 |
| 点击此处可从《中国科学通报(英文版)》下载免费的PDF全文 |