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冲绳海槽的地震反射波组,根据变形程度分为三组,即未变形的A层组,微变形的B层组和严重变形的c层组。局部地区出现D层组。A层组的地质年代可能是更新统至现代的沉积,海槽南段较厚,其旅行时最大近2秒,北段较薄,最薄约0.3秒。B层组可能是上新统的沉积,其厚度变化与A层组相反,南段薄,北段厚。C层组则可能是中新统和比中新统更老的地层。 海槽中充分发育着顺海槽走向的高角度正断层,为海槽的裂陷成因提供了可靠的依据。
The seismic reflection wave set in the Okinawa Trough is divided into three groups according to the degree of deformation, namely, the undeformed A-layer group, the micro-deformed B-layer group, and the severely deformed c-layer group. D zone group appeared in some areas. The geologic age of layer A may be from Pleistocene to modern sedimentation. The south section of the trough is thicker, with the maximum travel time of nearly 2 seconds, the northern section thinner and the thinnest about 0.3 seconds. Layer B may be the deposition of the Pliocene. The thickness of the layer B is opposite to that of the layer A, while the thickness of the south and the north are thicker. The C-Formation may be the older Miocene and Middle Miocene strata. Well-developed high-angle normal faults along the trough in the trough provide a reliable basis for the genesis of the trough.