Stochastic model of source parameters for strong-motion simulation

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K04620
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 25030:Disaster prevention engineering-related
• 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, 主任研究員 (30770309)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: 地震動予測 / 地震動シミュレーション

Outline of Final Research Achievements

In this study, we examined a method to generate a new set of seismic waveform data from an existing set of earthquake motion simulation waveforms for a certain number of scenarios, in order to create a group of predicted seismic waveforms that ensure the diversity of source parameters of the earthquake fault models assumed in earthquake motion prediction. We calculated the Wavelet Packet (WP) coefficients as the characteristic quantities in the time and frequency domains of the time history waveform data, and by estimating the probability density distribution of the latent variables reduced from the WP coefficients, we generated new waveform data samples following the distribution of the characteristics of the original waveform data set. We discussed the relationship between the probability density function that the latent variables follow and the seismic motion characteristics of the generated group of seismic motion waveforms.

Free Research Field

応用地震学

Academic Significance and Societal Importance of the Research Achievements

本研究では断層モデルや複雑な地盤構造の不確かさを考慮した大量の地震動シミュレーションを一つ一つ行うことなく、一定数の既存の地震動シミュレーション波形群を用いて、想定される地震断層モデルの震源パラメータの多様性を担保した入力地震動波形群を作成する手法を開発した。これによって適切な分布を持ったシミュレーション地震波形群の作成が可能となり、強震観測記録が活用されている経験的な地震動予測における観測記録の補填や、特定地点や構造物の地震リスク評価のための入力地震動などにおける利用が期待される。