Ray equation migration of wide-angle reflections in Dabie orogenic zone |
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| Authors: | Xu-Yao Zheng Chun-Yong Wang Xiao-Ling Lai and Xian-Kang Zhang |
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| Institution: | (1) Research Center of Exploration Geophysics, State Seismological Bureau, 450003 Zhengzhou, China;(2) Institute of Geophysics, State Seismological Bureau, 100081 Beijing, China |
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| Abstract: | Ray equation migration of wide-angle reflections in 2-D medium is one kind of Kirchhoff prestack depth migration method. Based
on ray theory, this method can be used extensively in 2-D inhomogeneous medium, and shows its advantage in wide-angle reflection
study. After calculating ray fields, we can get the wave fields of sources and receivers by interpolation, and the intensity
(or amplitude) A
p
corresponding to the depth point P at travel-time t
P
=t
SP
+t
PR
can be found in seismograms. Ray equation migration is completed by transforming A
P
according to the specific relation, migrating it to the depth point, then calculating the ray fields of lots of sources and
receivers in the same way and finally stacking the outcomes. Numerical calculation has yielded satisfactory results. Data
processing of the Zhuangmu-Yuexi-Huangmei-Zhanggondu profile passing through the Dabie orogenic zone provides a structural
form of M-discontinuity along the profile. The result shows that the high pressure metamorphic rock zone of South Dabie rock
mass is related to the uplifting of M-discontinuity here. "Mountain root" exists under North Dabie rock mass, which conforms
with gravity isostasy theory. The Xiaotian-Mozitan fault is a suture zone as a result of the collision of North China plate
with Yangtze plate, and extends through M-discontinuity. The abyssal fault near Liu’an is the extended eastern section of
the Luonan-Minggang fault, which is also confirmed here.
Contribution No. RCEG 96012, Research Center of Exploration Geophysics, SSB, China.
This project was supported by the National Natural Science Foundation of China and the Chinese Joint Seismological Science
Foundation. |
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| Keywords: | ray equation migration seismic profile M-discontinuity abyssal fault Dabie orogenic zone |
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