このエントリーをはてなブックマークに追加
ID 48724
本文ファイル
著者
Maekawa, Yuka
Hirono, Tetsuro
Mukoyoshi, Hideki
Kitamura, Manami
Ikehara, Minoru
Tanikawa, Wataru
Ishikawa, Tsuyoshi
キーワード
Carbonaceous material
Thermal maturation
Fault friction
Chelungpu fault
抄録(英)
To estimate the slip parameters and understand the fault lubrication mechanism during the 1999 Taiwan Chi-Chi earthquake, we applied vitrinite reflectance geothermometry to samples retrieved from the Chelungpu fault. We found a marked reflectance anomaly of 1.30% ± 0.21% in the primary slip zone of the earthquake, whereas the reflectances in the surrounding deformed and host rocks were 0.45% to 0.77%. By applying a kinetic model of vitrinite thermal maturation together with a one-dimensional heat and thermal diffusion equation, we determined the shear stress and peak temperature in the slip zone during the earthquake to be 1.00 ± 0.04 MPa and 626°C ± 25°C, respectively. Taking into account the probable overestimation of the temperature owing to a mechanochemically enhanced reaction or flash heating at grain contacts, this temperature should be considered an upper limit. The lower limit was previously constrained to 400°C by studies of fluid-mobile trace-element concentrations and magnetic minerals. Therefore, we inferred that the peak temperature during the Chi-Chi earthquake was 400°C to 626°C, corresponding to an apparent friction coefficient of 0.01 to 0.06. Such low friction and the previous evidence of a high-temperature fluid suggest that thermal pressurization likely contributed to dynamic weakening during the Chi-Chi earthquake.
内容記述
This study was supported by a Japan Ministry of Education, Culture, Sports, Science and Technology Grant-in-Aid for Young Scientists (A) 23684039, 2013.
掲載誌名
Earth, Planets and Space
66巻
開始ページ
28
出版年月日
2014-05-01
出版者
Springer Open
ISSN
1880-5981
出版者DOI
言語
英語
NII資源タイプ
学術雑誌論文
広大資料タイプ
学術雑誌論文
DCMIタイプ
text
フォーマット
application/pdf
著者版フラグ
publisher
権利情報
© 2014 Maekawa et al.; licensee Springer. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited.
関連情報URL
部局名
理学研究科