| Summary: | New methods are presented for processing and interpretation of shallow marine differential magnetic data, including constructing maps of offshore total magnetic anomalies with an extremely high resolution of up to 1–2nT, mapping weak anomalies of 5–10nT caused by mineralization effects at the contacts of hydrocarbons with host rocks, estimating depths to upper and lower boundaries of anomalous magnetic sources, and estimating thickness of magnetic layers and boundaries of tectonic blocks. Horizontal dimensions of tectonic blocks in the so-called “seismic gap” region in the central Kuril Arc vary from 10 to 100km, with typical dimensions of 25–30km. The area of the “seismic gap” is a zone of intense tectonic activity and recent volcanism. Deep sources causing magnetic anomalies in the area are similar to the “magnetic belt” near Hokkaido.
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