A new non-linear inversion approach: Applications for various research areas from waveforms and 2-D images

2017 Fiscal Year Final Research Report

• Project/Area Number: 16K13869
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Solid earth and planetary physics
• Research Institution: Hokkaido University
• Principal Investigator: Yomogida Kiyoshi 北海道大学, 理学研究院, 教授 (70230844)
• Co-Investigator(Renkei-kenkyūsha): YOICHIRO TAKADA 北海道大学, 理学研究院, 教授 (80466458)
• Research Collaborator: RYOU HONDA 神奈川県温泉地学研究所, 研究員 (80416081)
• Project Period (FY): 2016-04-01 – 2018-03-31
• Keywords: 波形解析 / 相互相関 / 位相の周期性 / ウィーナーフィルタ / スペクトル比 / S波偏向異方性 / 分散

Outline of Final Research Achievements

We have developed a new approach to compare waveform records with a criterion in the use of the time-domain Wiener filter, in order to remove the non-uniqueness originated from the periodicity in phase information. In the case of a short record length (e.g., multiple ScS phases on the core-mantle boundary of the earth), our approach can estimate broadband results accurately, compared with conventional spectral ratios. Another example in this study is the estimation of seismic anisotropy in the crust with the S-wave splitting of two horizontal-component records. In additional to the azimuth of splitting, our approach can estimate the time delay or the strength of anisotropy accurately, not resolved in a quantitative manner yet in previous studies. These results imply that our new approach is not only powerful for seismic waveform data, as shown in this study, but also any waveform records in a wide range of research areas, including two-dimensional image data in space.

Free Research Field

固体地球物理学