Fig. 3

Observed and calculated H/V of earthquake ground motion with estimated underground structures. a Observed (gray) and calculated (black) EHVSR at TTR002 site. b Observed MHVSR near the TTR002 site. c S wave velocity model with the results of 21 cases performed with different initial random numbers (gray lines), the most suitable solution (bold line) from which black line of (a) is calculated, and the search range (thin solid lines). Detailed parameters of the most suitable solution are shown in Additional file 1: Table S1. The dashed line indicates J-SHIS model (National Research Institute for Earth Science and Disaster Resilience 2019b) with PS-logging data at TTR002 site. d Same as (c) but for attenuation model