“…(1) hodogram techniques based upon the particle motion of direct arrivals, which is the simplest method and using only one three-component (3C) sensor (Albright and Hanold, 1976), (2) triangulation schemes based upon arrival times of direct waves by combinations of P-and/or S-waves at multiple stations (Gibowicz and Kijko, 1994), and (3) semblance methods based upon stacking waves without arrival-time picking. All three classes of location techniques can be used in conjunction with surface or downhole sensors (Duncan and Eisner, 2010). However, many researchers have developed other approaches on passive seismic emission tomography such as long-time-interval stacking similar to semblance (Kuznetsov et al, 2006;Kochnev et al, 2007) and picking the maximum amplitude of the P-wave migration as the imaging condition (Chambers et al, 2008(Chambers et al, , 2009a(Chambers et al, , 2009bRobein et al, 2009).…”