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The MT data at the Okchon Belt show peculiar phase responses exceeding 90o. A reasonable explanation is thatthose responses are due to an electrical anisotropy structure which is composed of a narrow anisotropic block and ananisotropic layer. Considering the dominant anisotropic strikes of the block (NE-trend) and the layer (NW-trend) inferred fromthe MT data, if existing, the electrical anisotropy in the Okchon Belt was probably produced by the deformations in the pre-Jurassic period, since the NE-trending shearing or thrusting should create alternating bands of metamorphic rocks and fractureswith NE-trending. Correlation of the structural strike of 2-D block with the latest EW-trending deformation eventsdemonstrates that the geometrical structure of the anisotropic block was formed by the latest Daebo and Bulgugsa orogeny. ......... electrical anisotropy, magnetotellurics, Okchon Belt, phases exceding 90o. . : ...... ..... ..... ... 90o