Corrigendum: Precise Monitoring of Pore Pressure at Boreholes Around Nankai Trough Toward Early Detecting Crustal Deformation - Ariyoshi, Keisuke; Kimura, Toshinori; Miyazawa, Yasumasa; Varlamov, Sergey; Iinuma, Takeshi; Nagano, Akira; Gomberg, Joan; Araki, Eiichiro; Miyama, Toru; Sueki, Kentaro; Yada, Shuichiro; Hori, Takane; et al. (Frontiers in Earth Science, 2021)