Comparison of hypocenter distribution in cluster A from different location methods. (a) Hypocenters from the JMA catalog. (b) Hypocenters relocated using the homogeneous station method. (c) Hypocenters relocated using the hypoDD technique. Seismicity from September 28, 2012 to April 11, 2013. The circle size represents the earthquake magnitude. Crosses with dashed circles in the upper right in (b) and (c) show the estimated location error. The inverted triangle indicates the location of the temporary station.