Electrical resistivity tomography (ERT) has been used to experimentally detect shallow buried faults in urban areas in the past a few years, with some progress and experience obtained. According to the results from Ol...Electrical resistivity tomography (ERT) has been used to experimentally detect shallow buried faults in urban areas in the past a few years, with some progress and experience obtained. According to the results from Olympic Park, Beijing, Shandong Province, Gansu Province and Shanxi Province, we have generalized the method and procedure for inferring the discontinuity of electrical structures (DES) indicating a buried fault in urban areas from resistivity tomograms and its typical electrical features. In general, the layered feature of the electrical structure is first analyzed to preliminarily define whether or not a DES exists in the target area. Resistivity contours in resistivity tomograms are then analyzed from the deep to the shallow. If they extend upward from the deep to the shallow and shape into an integral dislocation, sharp flexure (convergence) or gradient zone, it is inferred that the DES exists, indicating a buried fault. Finally, horizontal tracing is be carried out to define the trend of the DES. The DES can be divided into three types-type AB, ABA and AC. In the present paper, the Zhangdian-Renhe fault system in Zibo city is used as an example to illustrate how to use the method to infer the location and spatial extension of a target fault. Geologic drilling holes are placed based on our research results, and the drilling logs testify that our results are correct. However, the method of this paper is not exclusive and inflexible. It is expected to provide reference and assistance for inferring the shallow buried faults in urban areas from resistivity tomograms in the future.展开更多
北大西洋淡水注入触发的千年尺度气候突变事件发生在不同地球轨道背景下,理解地球轨道参数对印度夏季风千年尺度变率特征的调节作用,对理解未来印度夏季风对北大西洋淡水注入的响应具有重要的科学意义。本研究利用通用地球系统模式CESM...北大西洋淡水注入触发的千年尺度气候突变事件发生在不同地球轨道背景下,理解地球轨道参数对印度夏季风千年尺度变率特征的调节作用,对理解未来印度夏季风对北大西洋淡水注入的响应具有重要的科学意义。本研究利用通用地球系统模式CESM,探讨印度夏季风在8.2 ka B.P.和4.2 ka B.P.对相同北大西洋淡水注入的响应差异。模拟结果显示,北大西洋淡水注入使得印度夏季风强度显著减弱,其中夏季风降水变化在这两次事件中没有显著的空间差异,但变化幅度在4.2 ka B.P.要显著大于其在8.2 ka B.P.,表明地球轨道参数对印度夏季风千年尺度变率特征具有重要的调节作用。进一步分析显示,地球轨道并非通过影响温盐环流强度进行调节,而与夏季太阳辐射的高低有关。在4.2 ka B.P.时,在相同的淡水注入下,由于夏季太阳辐射较低,加剧了北大西洋的降温,同时也增强了其对下游大气的冷却作用,使得欧亚大陆南部对流层中上层大气具有更大的降温幅度,这进一步削弱了欧亚大陆南部与赤道印度洋对流层中上层大气的经向温度梯度,从而导致印度夏季风相较于8.2 ka B.P.具有更大的衰退幅度。因此,在较低夏季太阳辐射背景下,印度夏季风对北大西洋淡水注入的响应更为敏感。展开更多
基金The project entitled "Urban Active Fault Surveying Project"(143623) funded by the National Development and Roform Commission of China"Active Faults Exploration and Seismic Hazard Assessment in Zibo City"(SD1501) funded by the Department of Science & Technology of Shangdong Province,China
文摘Electrical resistivity tomography (ERT) has been used to experimentally detect shallow buried faults in urban areas in the past a few years, with some progress and experience obtained. According to the results from Olympic Park, Beijing, Shandong Province, Gansu Province and Shanxi Province, we have generalized the method and procedure for inferring the discontinuity of electrical structures (DES) indicating a buried fault in urban areas from resistivity tomograms and its typical electrical features. In general, the layered feature of the electrical structure is first analyzed to preliminarily define whether or not a DES exists in the target area. Resistivity contours in resistivity tomograms are then analyzed from the deep to the shallow. If they extend upward from the deep to the shallow and shape into an integral dislocation, sharp flexure (convergence) or gradient zone, it is inferred that the DES exists, indicating a buried fault. Finally, horizontal tracing is be carried out to define the trend of the DES. The DES can be divided into three types-type AB, ABA and AC. In the present paper, the Zhangdian-Renhe fault system in Zibo city is used as an example to illustrate how to use the method to infer the location and spatial extension of a target fault. Geologic drilling holes are placed based on our research results, and the drilling logs testify that our results are correct. However, the method of this paper is not exclusive and inflexible. It is expected to provide reference and assistance for inferring the shallow buried faults in urban areas from resistivity tomograms in the future.
文摘北大西洋淡水注入触发的千年尺度气候突变事件发生在不同地球轨道背景下,理解地球轨道参数对印度夏季风千年尺度变率特征的调节作用,对理解未来印度夏季风对北大西洋淡水注入的响应具有重要的科学意义。本研究利用通用地球系统模式CESM,探讨印度夏季风在8.2 ka B.P.和4.2 ka B.P.对相同北大西洋淡水注入的响应差异。模拟结果显示,北大西洋淡水注入使得印度夏季风强度显著减弱,其中夏季风降水变化在这两次事件中没有显著的空间差异,但变化幅度在4.2 ka B.P.要显著大于其在8.2 ka B.P.,表明地球轨道参数对印度夏季风千年尺度变率特征具有重要的调节作用。进一步分析显示,地球轨道并非通过影响温盐环流强度进行调节,而与夏季太阳辐射的高低有关。在4.2 ka B.P.时,在相同的淡水注入下,由于夏季太阳辐射较低,加剧了北大西洋的降温,同时也增强了其对下游大气的冷却作用,使得欧亚大陆南部对流层中上层大气具有更大的降温幅度,这进一步削弱了欧亚大陆南部与赤道印度洋对流层中上层大气的经向温度梯度,从而导致印度夏季风相较于8.2 ka B.P.具有更大的衰退幅度。因此,在较低夏季太阳辐射背景下,印度夏季风对北大西洋淡水注入的响应更为敏感。
