Fig. 7
Example distribution of the computed residual for source estimation. Distribution of the calculated normalized residual \(\epsilon\) at 13:00 on 15 December 2013. In the map view, the estimated source location of continuous tremors is situated inside the crater, where two black lines cross. The cross sections in the NS and EW directions are along these lines. The crack-like conduit in which the source of repeated VLP events proposed by Yamamoto et al. (1999) is also shown by the gray rectangle and lines in the map and the cross sections, respectively