Nucleation process of an M2 earthquake in a deep gold mine in South Africa inferred from on-fault foreshock activity

Yabe, Yasuo; Nakatani, Masao; Naoi, Makoto; Philipp, Joachim; Janssen, Christoph; Watanabe, Takayoshi; Katsura, Taishi; Kawakata, Hironori; Dresen, Georg; Ogasawara, Hiroshi