Research Station on Seismo Electromagnetics, The University of Electro-Communications (UEC), 1-5-1 Chofugaoka, Chofu Tokyo 182-8585, Japan

Institute of Geophysics, China Earthquake Administration, Beijing 100081, China

Institute of Geophysics, China Earthquake Administration, Beijing 100081, China

Kashi observatory, Earthquake Administration of Xinjiang Uygur Autonomous Region, Xinjiang 844000, China

Research Station on Seismo Electromagnetics, The University of Electro-Communications (UEC), 1-5-1 Chofugaoka, Chofu Tokyo 182-8585, Japan

Hayakawa Institute of Seismo-Electromagnetics, Co. Ltd., UEC Incubation Center, Chofu Tokyo, Japan

Earthquake Analysis Laboratory, Information Systems Inc., Kita-aoyama 2-12-42-305, Minato-ku, Tokyo 107-0061, Japan