Fig. 2

Settings and an example of 3D CMT inversion in the Kanto region. a Simulation settings to evaluate Green’s functions. The regions enclosed by the blue dashed and red dotted lines represent the horizontal coverage of the simulation model regions for evaluating Green’s functions and long-period ground motion simulations, respectively. The triangles and crosses in the map denote the locations of the F-net stations and the assumed source grids, respectively. (b–d) an example of a CMT solution for an earthquake on June 8, 2017, the location and depth of the optimal solution, used stations, and depth variations of optimal solutions at each source grid. Colors of the focal mechanisms reflect values of variance reduction between observed and synthetic displacements in the 25–100 s period band. The numbers above the optimal solutions in (b) are the optimal centroid depths. The grey focal mechanism in (b) is the F-net MT solution of this earthquake. The blue triangles in (b) are used F-net stations. (c) Spatial variations of VRs along latitude-depth and longitude-depth planes. (d) Examples of comparisons between observed and synthetic displacements in the 25–100 s period band. Gray solid and blue dotted lines are the observed and synthetic seismograms, respectively. Synthetic seismograms were evaluated by assuming the optimal solution. Amplitudes at each station were normalized by the maximum amplitude of observed and synthetic three-component displacement waveforms