An updated summary digital map of the anomalous magnetic field of Russia as a base for geo-modeling
- Russia Geological Research Institute, St. Petersburg, Russian Federation (tamara_litvinova@vsegei.ru)
A digital map of the anomalous magnetic field (AMF) of Russia has been created over 12 years in the monitoring (update) mode. The map was built from the level of the normal magnetic field Т n VSEGEI-1965 at a scale of 1: 2,500,000 using materials that were not previously involved in the process of summary mapping, taking into account modern digital technologies. The base of digital cartographic data contains grids on the network of 2,500 ×2,500 and 5,000×5,000 m and cartographic projects in * .mxd.
The anomalous component is of particular interest in the study of geodynamic processes and dynamic environments in the earth's crust and upper mantle. It is believed that the anomalous (short-wave or high-frequency) component, being a quasi-stationary (Lugovenko V.N., 1982) function of the general geomagnetic field, almost does not change over time. However, when calculating it, the primary role is played by the correct registration of the secular variation and the normal field, which change both in time and in space, and these changes are closely related to the dynamic processes inside the Earth. The works of T. Nagata (1969), F. Stacey (1974, 1977), Yu.P. Skovorodkin and L.S. Bezugloy (1980), V.A. Shapiro (1983) and others showed that the anomalous magnetic field of the Earth is also characterized by temporary changes associated with the dynamics of field sources, manifested in anomalies of the secular course. There is a connection between the secular variation anomalies and regional medium-scale anomalies. Within the Manchazh regional anomaly, the anomalous magnetic field increases monotonically at a rate of up to ±5 nT per year. It has been established that the source of the Manchazh anomaly is a block of rocks with increasing remanent magnetization, the mechanism of which is still unclear. The relationship between AMF changes with changes in the seismic regime and with individual earthquakes is evidenced by changes in the amplitudes of temporary changes in the local field from 5-8 nT at the Carpathian geodynamic test site and up to 30-80 nT during the Moneron earthquake on southern Sakhalin. Changes up to the first tens of nT AMFs were recorded several days before the Tashkent earthquake (Ulomov, 1967). During this earthquake, the author of this article observed the glow of the atmosphere, which indicates strong short-term changes in the variable geomagnetic field, which caused ionization processes in the surface layers of the atmosphere.
The Earth's magnetic field is 99% generated by its internal sources and reacts sensitively to nonequilibrium phase transitions of a different hierarchical class, which are the basis for the self-organization of the planet Earth system. On the map of magnetic anomalies of Russia, geostructures of different orders of rectilinear, circular, arcuate mosaic forms of anomalies are clearly distinguished, grouped into systems, the shape and size of which allows to reasonably judge the geodynamic conditions of their formation.
How to cite: Litvinova, T.: An updated summary digital map of the anomalous magnetic field of Russia as a base for geo-modeling, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-3292, https://doi.org/10.5194/egusphere-egu21-3292, 2021.
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