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| | Abstract | | Our group conducted microtremor array surveys at 26 points in Kumamoto Plain after the Kumamoto Earthquake in 2016 and made the 3D subsurface structural model in order to recalculate strong motions occurred by the earthquakes and to estimate the property of ground motions around Kumamoto Plain. We obtained dispersion curves and H/V spectrums from the microtremor array surveys. Then, we calculated the 1D structural model at each array by inverting the dispersion curves and H/V spectrums simultaneously. We made the 3D subsurface structural model from the seismic basement to the engineering basement with 0.25 km horizontal interval based on the J-SHIS model made by using the 1D structural models. In the area with where is no 1D structural model, the subsurface structural model created using relation between 1D structural models and gravity data in GALILEO (AIST). The 3D structural model indicates that the velocity layers of deep parts are deepening from Aso caldera toward Ariake Sea, and that graben-like structures run northeast along Kiyama River and north along Tsuboi River. |
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