Magnetotelluric surveys were carried out to investigate the electrical resistivity structure of the seismogenic region of the 1962 Northern Miyagi Earthquake (M6.5) in Miyagi Prefecture, northeastern Japan. A 2-D inversion reveals the existence of a deep conductive zone and overlying resistive zone in the upper crust. A positive aeromagnetic anomaly is also recognized above the resistive zone, which is interpreted as a buried Kitakami granitoid pluton. By comparison with the seismicity, we found that the microearthquakes occur just above the deep conductor and in the resistive zone, and that several S-wave reflectors are just above the deep conductor. Since the S-wave reflectors suggest the existence of fluid beneath them, the deep conductor can be interpreted as a fluid-filled zone. Moreover, we suggest that the seepage of the fluid from the conductive fluid-filled zone to the resistive granitoid pluton can become a trigger of the earthquakes. ¿ 2001 American Geophysical Union