A study on the generation of long-period ground motions in large-scale sedimentary basins

2017 Fiscal Year Final Research Report

• Project/Area Number: 15K05272
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Solid earth and planetary physics
• Research Institution: Yokohama City University
• Principal Investigator: YOSHIMOTO Kazuo 横浜市立大学, 生命ナノシステム科学研究科(八景キャンパス), 教授 (10281966)
• Co-Investigator(Kenkyū-buntansha): 中原 恒 東北大学, 理学研究科, 准教授 (20302078)
• Project Period (FY): 2015-10-21 – 2018-03-31
• Keywords: 長周期地震動 / 堆積盆地 / 堆積層

Outline of Final Research Achievements

By analyzing the long-period ground motions (LPGs) during moderate to large earthquakes recorded in the Kanto sedimentary basin, we found that the amplitude and dominant period of the Fourier velocity spectrum of LPGs is large and long for the horizontal motions compared with the vertical motions, indicating that the Love wave is dominant in the LPGs. We also found that the dominant period of LPGs becomes longer in the middle part of the Boso peninsula.
Our 3D numerical simulation of LPGs using a seismic velocity structure model called the Smoothed Basin Velocity Structure Model (SBVSM) demonstrated that this model has a potential to explain observed amplitude and envelope of LPGs in the Kanto sedimentary basin, except for the Tokyo bay area including the middle part of the Boso peninsula.

Free Research Field

数物系科学