2019 Fiscal Year Final Research Report
Research on inversion of irregular structure of deep sediments near fault
Project/Area Number |
17K01324
|
Research Category |
Grant-in-Aid for Scientific Research (C)
|
Allocation Type | Multi-year Fund |
Section | 一般 |
Research Field |
Natural disaster / Disaster prevention science
|
Research Institution | Tokyo Institute of Technology |
Principal Investigator |
Yamanaka Hiroaki 東京工業大学, 環境・社会理工学院, 教授 (00212291)
|
Project Period (FY) |
2017-04-01 – 2020-03-31
|
Keywords | 波形逆解析 / 堆積層 / S波速度 / 長周期地震動 / ラブ波 / 地震波干渉法 / 2次元速度構造 / 深部地盤 |
Outline of Final Research Achievements |
We have proposed an inversion methods of Love wave in earthquake records to a 2D S-wave profile of deep sedimentary layers including basin edge shapes. The inversion method consists of a preprocessing of earthquake records and a waveform inversion. We applied a principle-axis analysis to horizontal motions of earthquake records to select stations at every period for the waveform inversion. We conducted numerical tests with synthetic earthquake records generated using a 3D calculation. After the validation of the method in the tests, we applied the method to actual long-period earthquake records observed in the western part of Kanto basin. The inverted 2D profiles including basin edges along several lines are used to improve an existing 3D basin model. The revised model shows a higher performance to estimate features of earthquake ground motions than the original one. The proposed method is capable to deduce a S-wave velocity model suitable for predicting earthquake ground motion.
|
Free Research Field |
地震工学
|
Academic Significance and Societal Importance of the Research Achievements |
堆積平野の地震動は、地下のS波速度構造の影響を強く受けており、その予測には、信頼性の高いS波速度構造の情報が必要である。とくに、長周期地震動は、地震基盤に至るまでの深部地盤の影響が大きいことが知られている。本研究によって提案した方法を用いて、堆積平野の地震記録から精度の高い深部地盤モデルを推定でき、それらを超高層建物や長大橋などの長周期構造物の耐震設計のための地震動評価などで活用することができる。さらに、本手法を全国の主要な堆積平野の深部地盤構造のモデル化に適用することによって、各地域の地震被害想定や地震動予測マップなどの信頼性の向上にも寄与できると期待される。
|