The Research On The Magnetotelluric Method Of The Combination Of Ocean And Land

The rapid increase of world population, excessive consumption of scarceresources in the recent decades made people begin to recognize that land resources arelimited and can not meet the need of human. Therefore, many countries around theworld are focusing on the mysterious ocean. China has a unique advantage with32,000kilometers of coastline and three million square kilometers of marine area.More than70percent the Earth’s surface area is ocean, which containunimaginable wealth of resources. There are35billion tons of recoverable reservesof oil and14billion cubic meters of natural gas resources in the ocean. A largenumber of coal, iron and other solid mineral are also in the ocean, more than20kindsare found in China including gold, silver and platinum and other high valuablemineral; the ocean also has a considerable stock of hydrothermal mineral. In the ocean,there is a combustible ice which has no pollution after burning. In the South ChinaSea and the East China Sea, there is combustible ice. Therefore, how to carry out theinvestigation of marine resources better will be the main subject of attention in thefuture.Geophysical exploration has played a huge role in ocean exploration.Geophysical exploration methods detect the Earth’s interior through the differentphysical characteristics of the various media. Land-based geophysical explorationmethod has become an important means to find resources after decades ofdevelopment. However, the marine geophysical exploration has just started, it will bemature slowly with the progress of science and technology development andobservation means. Marine seismic survey has been able to play a major role in theproduction practice.Electrical prospecting is also very important as an important branch of the geophysical exploration methods in the exploration of marine resources. Electricalprospecting can be divided into artificial source and natural field sources,magnetotelluric sounding method is widely used as an artificial sources method. Butwhen it comes to the ocean, MT method will have trouble because the seawater in themarine is a low-pass filter which has a strong absorption of high frequencyelectromagnetic signal. This paper will discuss and investigate what influence theseawater will bring to electrical anomaly body and is to investigate the electricalprospecting the magnetotellurical sounding method in respect of land and sea surveys.China is strongly supporting the university to do research in the ocean resourcesurvey in recently years to discover the marine resource. This paper is supported bynational ocean863project charged by China University of Geoscience in Beijing.Preliminary work is build many models with marine layer after the establishment of alarge number of marine geological conditions. And then, these inversion models willbe played forward. The inversion models will be inversion based on the results of theforward. To know the influence of the marine layer by the comparison of differentmodels. The main purpose is to identify which inversion of the anomalous body maybe due to the water layer lead to false anomalies, which the anomalous body is real.The following results are obtained after the study:1) find the influence of the seawater layer on the inversion results after thecomparison of the inversion results of different models.2) how to get better inversion results in different situations by the choice ofinversion parameters and the inversion model.3) after the research of simple model, building some complex models and analyzethe inversion results of them to sum up a simple way to judge false anomalies and sealevel impact.