Fig. 4From: Coseismic changes in groundwater level during the 2018 Hokkaido Eastern Iburi earthquakeAmplitude responses and phase shifts of the M2 tidal constituent (period: 12.4206 h) with respect to the phase in the GOTIC2 data between September 2017 and October 2018. Error bars are one sigma. The responses were calculated every 31 days using the BAYTAP-G tidal analysis software. The solid line indicates the timing of the earthquakeBack to article page