Relative Hypocenter Location Algorithm Registering past earthquakes (hypoTD) Relative Hypocenter Location Algorithm Registering past earthquakes (hypoTD): Method and Application to Earthquakes beneath the Japanese Islands By Shigeki Horiuchi, Shuken Wada, Yuko Sato, Minoru Yoshida, Yoshiharu Hirayama, Hiroyuki Fujiwara