Scientists use the noise of marine environment to see the three -dimensional geological structure of the coral island reef

Recently, Xia Shaohong, a researcher at the Edge Sea and Ocean Geological Key Laboratory of the South China Sea Institute of Chinese Academy of Sciences, aimed at breaking through the shallow three -dimensional fine imaging of the coral island reef on the body. Related research results have recently been published in the TOP journal ENGINEERING "Engineering" in the field of engineering.

(A) The noise waveform of the isolated islands and reefs in the ocean in the ocean; (b) the result of the interrelationship between the noise of 12 hours; Interoperability results. The red line in the figure represents the transmission speed of 1.3 km/s.

As the precious land and resources in the ocean, the coral island reef is not only an important base for the development of marine resources and the protection of marine rights and interests, but also an important carrier of cutting -edge scientific issues such as the evolution of regional structural evolution and global environmental changes. There are a large number of coral islands and reefs in the South my country Sea, with a total area of ​​about 37200 km2, forming a unique marine landform landscape with islands and reefs. In the process of forming the evolution of these coral islands and reefs, they were affected by factors such as climate, sea level changes, and island sinking and lifting. The development and utilization of potential geological disasters and hidden dangers also provided the ideal window for studying the evolution and environmental changes in the South China Sea. However, due to the restrictions on operating conditions, it is difficult for traditional marine earth physical technology and drilling samples to show the fine three -dimensional superficial geological structure of the coral islands and reefs, and the operating costs are high and efficient. Therefore, how to develop an economic high -efficiency three -dimensional imaging technology suitable for the special environment of coral islands and reefs is an urgent problem that needs to be solved in the development and utilization of coral island reef projects and sustainable development.

(A) The sliced ​​diagram of different depths of the three -dimensional S -wave speed structure of the island and reef. The black star is a seismic station, and the gray cylinder is the drilling position; The pore degree changes with depth;

Researchers conducted detailed analysis of marine environment noise data collection and noise signals by setting up a dense earthquake station on the typical islands and reefs in the South China Sea. The results of the research show that the background noise signal of the isolated coral islands and reefs in the ocean can be roughly divided into three parts: below 1hzz, 1-5hrtz, and 5hrtz. Among them, the noise spectrum below 5 Hertz is characterized by good consistency in different stations. 5 There are significant differences in Herz or above. Through the comparative study of long -continuous waveforms at different times, the researchers have found that for the noise signals below the coral islands and reefs, the continuous waveform of the noise signal below of the coral islands 5 can obtain a high signal -to -noise ratio and symmetrical symmetry for 12 hours or 1 day. A good sexual correlation function provides an important basis for the three -dimensional structure of the island and reef in the future; the further three -dimensional formation of imaging results show that the superficial geological structure of the coral islands and reefs has obvious partition, and it is the island and reef to the sea to the sea The degree of difference in the degree of stratum tunnel on the side reef flats is consistent. At the same time, the study also found that there are two low -speed layers of coral island reef development, which has a good consistency with the high pore layer revealed by the drilling rock core sample, which reflects that the island reef formation process has experienced multiple stratum exposure and strong weathering during the formation of island reef formation. Geological event.

The study shows that using the rich environmental noise signals in the ocean can be economically efficient and environmentally friendly to obtain the fine structure of coral islands and reefs. It is one of the preferred plans for geological detection of islands and reef engineering in the future.

The research was completed by the Chinese Academy of Sciences Strategic Pioneer Science and Technology Special Mission (XDA13010101), Hainan Provincial Key R & D project (ZDYF2020198), and the Guangdong Special Branch Project Local Innovation and Entrepreneurship Team (2019BT02H594).

Text, Tu/Guangzhou Daily · Xinhua City Reporter: Longyu Correspondent: Li Shu Guangzhou Daily · Xinhuacheng Editor: Lin Jing

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