The preliminary interpretation of deep seismic sounding in western Yunnan |
| |
| Authors: | Zhong-Yang Lin Hong-Xiang Hu Wen-Bin Zhang Hui-Fen Zhang Zheng-Qin He Zhen-Ming Lin and Tao-Xing Qiu |
| |
| Institution: | (1) Institute of Geophysics, State Seismological Bureau, 100081 Beijing, China;(2) Geophysical Prospecting Brigade, State Seismological Bureau, 450003 Zhengzhou, China;(3) Seismological Bureau of Guangdong Province, 510070 Guangzhou, China;(4) Institute of Crustal Dynamics, State Seismological Bureau, 100085 Beijing, China;(5) Seismological Bureau of Fujian Provience, 350003 Fuzhou, China |
| |
| Abstract: | The preliminary interpretation of Project western Yunnan 86–87 is presented here. It shows that there obviously exists lateral
velocity heterogeneity from south to north in western Yunnan. The depth of Moho increases from 38 km in the southern end of
the profile to 58 km in its northern end. The mean crustal velocity is low in the south, and high in the north, about 6.17–6.45
km/s. The consolidated crust is a 3-layer structure respectively, the upper, middle and lower layer. P
1
0
is a weak interface the upper crust, P
2
0
and P
3
0
are the interfaces of middle-upper crust and middle-lower crust respectively. Another weak interface P
3
0′
can be locally traced in the interior of the lower crust. Interface Pg is 0–6 km deep, interface P
1
0
9.2–16.5 km deep, and interfaces P
2
0
and P
3
0
respectively 17.0–26.5 km, 25.0–38.0 km deep. The velocity of the upper crust gradually increases from the south to the north,
and reaches its maxmium between Nangaozhai and Zhiti, where the velocity of basement plane reaches 6.25–6.35 km/s, then it
becomes small northward. The velocity of the middle crust varies little, the middle crust is a low velocity layer with the
velocity of 6.30 km/s from Jinhe-Erhai fault to the north. The lower crust is a strong gradient layer. There exists respectively
a low velocity layer in the upper mantle between Jinggu and Jingyunqiao, and between Wuliangshan and Lancangjiang fault, the
velocity of Pn is only 7.70–7.80 km/s, it is also low to the north of Honghe fault, about 7.80 km/s. Interface P6/0 can be traced on the top of the upper mantle, its depth is 65 km in the southern end of the profile, and 85 km in the northern
end.
The Chinese version of this paper appeared in the Chinese edition ofActa Seismologica Sinica,15, 427–440, 1993. |
| |
| Keywords: | deep seismic sounding western Yunnan region velocity structure deep and larger fault |
| 本文献已被 SpringerLink 等数据库收录！ |
|
