*Asako Iwaki¹, Nobuyuki Morikawa¹, Takahiro Maeda¹, Hisahiko Kubo¹, Hiroyuki Fujiwara¹ (1.National Research Institute for Earth Science and Disaster Resilience)

*Kei Katsumata¹, Mako Ohzono¹, Hiroshi Aoyama¹, Ryo Tanaka¹, Masamitsu Takada¹, Masayoshi Ichiyanagi¹, Teruhiro Yamaguchi¹, Kazumi Okada¹, Hiroaki Takahashi¹, Shin'ichi Sakai², Satoshi Matsumoto³, Tomomi Okada⁴, Toru Matsuzawa⁴, Shuichiro Hirano⁵, Toshiko Terakawa⁶, Shinichiro Horikawa⁶, Masahiro Kosuga⁷, Hiroshi Katao⁸, Yoshihisa Iio⁸, Airi Nagaoka⁸, Noriko Tsumura⁹, Tomotake Ueno¹⁰, the Group for the Aftershock Observations of the 2018 Hokkaido Eastern Iburi Earthquake (1.Institute of Seismology and Volcanology, Faculty of Science, Hokkaido University, 2.Earthquake Research Institute, University of Tokyo, 3.Institute of Seismology and Volcanology, Faculty of Science, Kyushu University, 4.Research Center for Prediction of Earthquakes and Volcanic Eruptions, Graduate School of Science, Tohoku University, 5.Nansei-Toko Observatory for Earthquakes and Volcanoes, Graduate School of Science and Engineering, Kagoshima University, 6.Earthquake and Volcano Research Center, Graduate School of Environmental Studies, Nagoya University, 7.Graduate School of Science and Technology, Hirosaki University, 8.Research Center for Earthquake Prediction, Disaster Prevention Research Institute, Kyoto University, 9.Graduate School of Science, Chiba University, 10.National Research Institute for Earth Science and Disaster Prevention)

*Takayuki Kawabe¹ (1.Faculty of Education, Arts and Sciences, Yamagata University)

*Takashi Azuma¹, Daisuke Hirouchi², Koji Okumura³, Kaoru Taniguchi⁴, Masashi Omata⁴, Yorihide Kohriya⁴ (1.National Institute of Advanced Industrial Science and Technology, 2.Shinshu University, 3.Hiroshima University, 4.Pasco CORPORATION)

*Tatsuya Ishiyama¹, Naoko Kato¹, Hiroshi Sato¹, Taro Koike², Katsuya Noda² (1.Earthquake Research Institute, University of Tokyo, 2.Geosys, Inc. )

*Satoshi Fujiwara¹, Hiroshi Une¹, Takayuki Nakano¹, Hiroshi Yarai¹, Tomokazu Kobayashi¹, Yu Morishita¹ (1.GSI of Japan)

*Ritsuya Shibata¹, Naofumi Aso¹, Junichi Nakajima¹, Satoshi Ide² (1.Department of Earth and Planetary Sciences, Tokyo Institute of Technology, 2.Department of Earth and Planetary Science, University of Tokyo)

*Ryoichi Nakamura¹, Takahiro Shiina¹ (1.Earthquake Research Institute, The University of Tokyo)

*Yoshio Murai¹, Kei Katsumata¹, Tetsuo Takanami², Tomoki Watanabe³, Tadashi Yamashina⁴, Ikuo Cho⁵, Masayuki Tanaka⁶, Ryosuke Azuma⁷ (1.Institute of Seismology and Volcanology, Faculty of Science, Hokkaido University, 2.Department of Terrestrial Magnetism, Carnegie Institution of Washington, 3.Marine Works Japan LTD, 4.Kochi University, 5.National Institute of Advanced Industrial Science and Technology, 6.Meteorological Research Institute, 7.Research Center for Prediction of Earthquakes and Volcanic Eruptions, Graduate School of Science, Tohoku University)

*Takaya Iwasaki¹, Noriko Tsumura², Tanio Ito³, Kazunori Arita⁴, Hiroshi Sato¹ (1.Eathquake Research Institute, the University of Tokyo, 2.Graduate School of Science, Chiba University, 3.Association for the Development of Earthquake Prediction, 4.Hokkaido Research Center of Geology)