The magnitudes of all the earthquakes detected in this study are body-wave magnitudes, determined from the maximum amplitudes of vertical-component seismograms recorded by the dense local seismic network and the NZWH (NIED) station; these magnitudes are in general consistent with the JMA magnitude scale. The magnitude (M6.2) of the Northern Nagano mainshock is a moment-magnitude (Mw), obtained by moment tensor analysis of the F-net (NIED) broadband seismograph network data. All the other event magnitudes are those reported in the JMA earthquake catalog.