Abstract—The results of geomagnetic studies in the Tashkent and Fergana geodynamic test sites, Uzbekistan, are presented. Detail analysis of anomalous geomagnetic variations caused by the processes occurring at different depths in the Earth’s crust and upper mantle is conducted. By their linear size, variations are divided into regional (100 km and larger) and local (1 to 5 km and larger). Regional anomalous variations manifest themselves by sinusoidal, bay-like, and trend forms and last one to seven years. In the trend-type variations, the gradient is 0.5–2.0 nT/yr. Local anomalous variations typically have sinusoidal and bay-like shape. Bay anomalies have both positive and negative sign, and the change is reversible. The intensity of the anomalies ranges from 2 to 25 nT and the duration is from 10–15 days to three years or even longer. The local anomalous variations are neither precursory nor technogenic. Numerous anomalies of this type were for the first time revealed at the geodynamic test sites in Uzbekistan. The analysis of the data for the past 40–50 years has shown the absence of information on this type of anomalous variations. They can neither be explained by conventional mechanisms responsible for secular behavior of the geomagnetic field, nor by lithologic composition of the rocks, tectonics fetures, hydrogeological conditions, and geophysical fields of the studied territories. One of the peculiarities of local anomalous variations of this type is that they can change in time, in shape, in size of the area, in intensity, and in sign. The published data relevant to the anomalies in the secular variation of the geomagnetic field have been analyzed. However, unfortunately, these data provide almost no information on the origin of local anomalous variations discussed in our work.

摘要— 介绍了乌兹别克斯坦塔什干和费尔干纳地球动力学试验场的地磁研究结果。对地壳和上地幔不同深度发生的过程引起的异常地磁变化进行了详细分析。根据其线性大小，变化分为区域（100 公里及更大）和局部（1 至 5 公里及更大）。区域异常变化以正弦、海湾状和趋势形式表现出来，并持续一到七年。在趋势型变化中，梯度为 0.5–2.0 nT/yr。局部异常变化通常具有正弦和海湾状形状。海湾异常有正负两种迹象，变化是可逆的。异常强度范围为 2 至 25 nT，持续时间为 10 至 15 天至三年甚至更长。局部异常变化既不是先兆也不是技术原因。在乌兹别克斯坦的地球动力学试验场首次发现了大量此类异常现象。对过去 40-50 年的数据分析表明，缺乏关于此类异常变化的信息。它们既不能用造成地磁场长期行为的传统机制来解释，也不能用岩石的岩性成分、构造特征、水文地质条件和研究区域的地球物理场来解释。这种类型的局部异常变化的特点之一是它们可以随时间、形状、区域大小、强度和符号发生变化。对已发表的与地磁场长期变化异常相关的数据进行了分析。然而，