Development of a new method for broadband ground-motion prediction based on simulations and observed records

2020 Fiscal Year Final Research Report

• Project/Area Number: 17K13000
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Natural disaster / Disaster prevention science
• Research Institution: National Research Institute for Earth Science and Disaster Prevention
• Principal Investigator: Iwaki Asako 国立研究開発法人防災科学技術研究所, マルチハザードリスク評価研究部門, 特別研究員 (30770309)
• Project Period (FY): 2017-04-01 – 2021-03-31
• Keywords: 強震動予測 / 広帯域地震動予測

Outline of Final Research Achievements

The applicability of the ground-motion prediction by deterministic simulations is limited to a certain period range due to the resolution of the source and the velocity models. Short-period ground motion (< ~1 s) is often simulated by stochastic or empirical approaches. We have proposed a method to simulate broadband ground motion taking advantage of the deterministically simulated long-period ground motion and the empirical ground-motion characteristics between long- and short-period bands. In this study we proposed several ways to update the method to apply it to strong-motion prediction in Kanto area, Japan, considering the difference in earthquake types and the detailed velocity structure model.

Free Research Field

応用地震学

Academic Significance and Societal Importance of the Research Achievements

本研究で検討した広帯域地震動波形合成手法は，従来の手法における長周期帯域と短周期帯域の予測手法の違いによる不整合を解消し，震源モデルや地下構造モデルに基づく理論的アプローチによる長周期帯域の情報と観測記録から得られる経験的な地震動特性を生かした実用的な手法である．関東地域における想定活断層の多数シナリオに対する広帯域地震動の予測を行い，予測結果の集合が観測記録と比べて，適切な分布をしているかどうかという観点から検証を行っており，今後，信頼性の高い広帯域地震動予測波形を用いた地域の地震ハザード評価への展開につながることが期待される．