In recent years, the necessity of constructing new geomagnetic observatories in Iran has been discussed from various aspects. Improper site selection of such important data centres can significantly affect the quality of their recorded data. In this research, site selection studies were performed to find the most favourable location to construct a geomagnetic observatory in Kerman Province, southeast of Iran. Having defined 11 site selection criteria for geomagnetic observatories, all the data layers were prepared for the whole province. After detection of seven promising regions using analytical hierarchy process and fuzzy logic method in geographical information system, Technique for Order of Preference by Similarity to Ideal Solution was used for ranking of the suitable areas. The most favourable region was finally detected southwest of Kerman Province, located between the cities of Baft and Sirjan. Detailed land surveys can be focused in this region to decide on the optimum area for the construction of the geomagnetic observatory. 相似文献
在青藏高原东南缘,前人使用大地电磁探测和地震学方法得出的结果都揭示了可能存在部分熔融状态的地壳流,而这种地下熔融体与周围物质的作用可能引起了地下强电流异常,进一步导致地表地磁响应.基于连续的地磁观测,发现2018年7月31日在川滇块体周边出现大范围的地磁Z分量日变化短时畸变,畸变发生后100天内发生了4次5级以上地震.为了定量研究这一现象,本文基于Biot-Savart定理和采用SVD(Singular Value Decomposition,奇异值分解)的阻尼最小二乘法对地磁日变化短时畸变数据开展反演.结果显示:(1)以大地电磁测深给出的电性模型作为初始条件,反演得到的电流强度为3700~5000 A,有效深度为25~60 km;(2)地下畸变电流的空间分布位置和深度和地下电性高导体分布一致,与前人给出的地壳流位置吻合;(3)地壳流偶然微小运动可能引起了大范围的强电流,这种短时存在的高强度电流沿高导带分布,可能是地磁日变化短时畸变的源电流;(4)推测深部地壳流的运动具有传递应力作用,参与诱发了100天内发生多次5级以上地震.对源电流进行反演的定量化工作,以地下电流的方式佐证了可能存在地壳流.