JpGU-AGU Joint Meeting 2017

講演情報

[EE] ポスター発表

セッション記号 S (固体地球科学) » S-IT 地球内部科学・地球惑星テクトニクス

[S-IT28] [EE] Seismic attenuation: Observations, Experiments, and Interpretations

2017年5月20日(土) 15:30 〜 17:00 ポスター会場 (国際展示場 7ホール)

コンビーナ:武井 康子(東京大学地震研究所)、Douglas Wiens(Washington University in St Louis)、竹内 希(東京大学地震研究所)

[SIT28-P06] Seismic Attenuation Tomography of Gofar Transform Fault, East Pacific Rise Using OBS Observations

*Haijiang Zhang1Jing Hu1Hao Guo1 (1.University of Science and Technology of China, School of Earth and Space Sciences)

キーワード:Gofar transform fault, Seismic attenuation tomography, Structure segmentation

Gofar transform fault of East Pacific Rise generates Mw 5.5-6 large earthquakes quasi-periodically on some segments of the fault, which are separated by stationary rupture barriers. Earthquakes in the seismic cycle of the large earthquake have clear spatial and temporal evolutions. To better understand the relationship between the earthquake behavior and the physical properties of the fault zone along the strike, Woods Hole Oceanographic Institution deployed a broadband ocean bottom seismograph (OBS) array on Gofar transform fault for 1-year continuous measurements, which successfully captured a Mw 6.0 earthquake on18 September 2008 and provided an unprecedented dataset. By using t* values determined from fitting seismic waveform frequency spectrum, we have conducted three-dimensional seismic attenuation tomography to determine along-strike attenuation structure. Combined with the high-resolution earthquake locations and Vp, Vs and Vp/Vs models determined from seismic velocity tomography, we found that the seismicity behavior is mainly controlled by structure heterogeneities along the fault.