Fig. 1From: Prevalence of asymmetrical rupture in small earthquakes and its effect on the estimation of stress drop: a systematic investigation in inland JapanSpatial distribution of the focal mechanisms and seismic stations used in this study. a Focal mechanisms (Mw 3.3–5.5) are shown by “beach ball” symbols. b Example AMRF distributions plotted at the locations of the seismic stations. Black arrows represent azimuths of rupture propagation. Tick marks denote 0.2 s intervals. c Relationships between azimuth and corner frequency of AMRFs. Black and gray curves show theoretical corner frequencies based on the best-fit generalized and symmetrical rupture models, respectively. For the computation, takeoff angles were assumed to be 90°. d The confidence regions of rupture propagation direction are shown on the beach balls symbols. Black squares show results within the confidence region. White squares show the best result. Crosses show the seismic stationsBack to article page