Fig. 5

Detected strain steps in the stacked strain from 2016 to 2022. a–e show the strain steps which indicated spatiotemporal correlations with tectonic tremor activities. Stacked strain changes are shown on the left side of each panel, and their \(r^2\) distributions are shown on the right. Dur, M\(_{\textrm{0}}\), CC\(_{\textrm{sr2}}\), and CC\(_{\textrm{st}}\) denote the estimated duration, the seismic moment, the correlation coefficient with a ramp function, and the correlation coefficient with the accumulated number of tectonic tremors of the strain step. The rectangle on each map shows a fault model used for the seismic moment estimation; the red line segment on the rectangle indicates the upper edge of the fault, and the green arrow indicates the slip direction. The blue dot indicates the fault center location assumed in the strain step detection described in “Detection of Strain Steps” section. Black circles with arrows indicate the locations of strainmeters used for the analysis, and the direction of each arrow indicates the strain-sensing direction. Open circles and the red dot denote the epicenters of tectonic tremors occurring during the strain step and their averaged location, respectively