氏名小原 一成
職名教授
所属観測開発基盤センター
専門観測地震学
URL http://www.eri.u-tokyo.ac.jp/obara/index.html

最終更新日 11/06 2014

研究内容

海洋プレートの沈み込み境界では、巨大地震の発生領域の周囲に、通常の地震に比べ卓越周期の長いスロー地震が発生する。スロー地震の代表例である深部低周波微動は、西南日本で世界で初めて発見された後、世界各地で検出されてきた。これらのスロー地震活動と巨大地震との関連を解明することを目標として、スロー地震メカニズム解明に関する研究、新たな地動現象の検出やスロー地震活動状況をさらに正確に把握するためのモニタリング手法の開発を進めている。

主要論文・著書

Obara, K. and T. Maeda, Reverse propagation of T waves from the Emperor seamount chain, Geophys. Res. Lett., 36, L08304, doi:10.1029/2009GL037454, , 2009.

Obara, K., Inhomogeneous distribution of deep slow earthquake activity along the strike of the subducting Philippine Sea Plate, Gondwana Research, 16, 512--526, 2009.

Obara, K. and S. Sekine, Characteristic activity and migration of episodic tremor and slow-slip events in central Japan, Earth Planets Space, 61, 853--862, 2009.

Maeda, T. and K. Obara, Spatiotemporal distribution of seismic energy radiation from low-frequency tremor in western Shikoku, Japan, J. Geophys. Res., 114, B00A09, doi:10.1029/2008JB006043, , 2009.

Ito, Y., K. Obara, T. Matsuzawa and T. Maeda, Very low frequency earthquakes related to small asperities on the plate boundary interface at the locked to aseismic transition, J. Geophys. Res., 114, B00A13, doi:10.1029/2008JB006036, , 2009.

Matsuzawa, T., K. Obara and T. Maeda, Source duration of deep very low frequency earthquakes in western Shikoku, Japan, J. Geophys. Res., 114, B00A11, doi:10.1029/2008JB006044, , 2009.

小原一成, フィリピン海プレート沈み込みに伴う西南日本のスロー地震群の発見, 地震2, 61, S315--S327, 2009.

Obara, K., Phenomenology of deep slow earthquake family in southwest Japan: Spatiotemporal characteristics and segmentation, J. Geophys. Res., 115, B00A25, doi:10.1029/2008JB006048, , 2010.

Obara, K. and M. Matsumura, Reverse Propagation of Surface Waves Reflected from a Sea Mountain range in the northwestern Pacific, Bull. Seism. Soc. Am., 100, 1342--1349, 2010.

Obara, K., T. Maeda, S. Tanaka and T. Matsuzawa, Depth-dependent activity of non-volcanic tremor in southwest Japan, Geophys. Res. Lett., 37, L13306, doi:10.1029/2010GL043679, , 2010.

Aoi, S., B. Enescu, W.Suzuki, Y. Asano, K. Obara, T. Kunugi and K. Shiomi, Stress transfer in the Tokai subduction zone from the 2009 Suruga Bay earthquake in Japan, Nature Geoscience, 3, 496--500, 2010.

Hirose, H. and K. Obara, Recurrence behavior of short-term slow slip and correlated non-volcanic tremor episodes in western Shikoku, southwest Japan, J. Geophys. Res., 115, B00A21, doi:10.1029/2008JB006050, , 2010.

Sekine, S., H. Hirose and K. Obara, Along-strike variations in short-term slow slip events in the southwest Japan subduction zone, J. Geophys. Res., 115, B00A27, doi:10.1029/2008JB006059, , 2010.

Ueno, T., T. Maeda, K. Obara, Y. Asano and T. Takeda, Migration of low frequency tremor revealed from multiple array analyses in western Shikoku, Japan, J. Geophys. Res., 115, B00A26, doi:10.1029/2008JB006051, , 2010.

Kimura, H., T. Takeda, K. Obara and K. Kasahara, Seismic Evidence for Active Underplating Below the Megathrust Earthquake Zone in Japan, Science, 329, 210--212, 2010.

Hirose, H., Y. Asano, K. Obara, T. Kimura, T. Matsuzawa, S. Tanaka and T. Maeda , Slow Earthquakes Linked Along Dip in the Nankai Subduction Zone, Science, 330, 1502, , 2010.

K.Obara, T.Matsuzawa, S.Tanaka, T.Kimura, and T.Maeda, Migration properties of non‐volcanic tremor in Shikoku, southwest Japan, Geophys. Res. Lett., 38, L09311, doi:10.1029/2011GL047110, , 2011.

K.Obara, Characteristics and interactions between non-volcanic tremor and related slow earthquakes in the Nankai subduction zone, southwest Japan, J. Geodynamics, 52, 229--248, 2011.

K.Obara, T.Matsuzawa and S.Tanaka, and T.Maeda, Depth-dependent mode of tremor migration beneath Kii Peninsula, Nankai subduction zone, Geophys. Res. Lett., 39, L10308, doi:10.1029/2012GL051420, , 2012.

K.Obara, New detection of tremor triggered in Hokkaido, northern Japan by the 2004 Sumatra–Andaman earthquake, Geophys. Res. Lett., 39, L20305, doi:10.1029/2012GL053339, , 2012.

Obara, K., Deep slow earthquake activities in Nankai subduction zone, southwest Japan -Overview and recent topics- , IRIS Workshop, Snowbird, UT (USA), 2010/6/11, , 2010.

Obara, K., Depth-dependent slip regime on the plate interface revealed from slow earthquake activities in the Nankai subduction, EarthScope Workshop, Portlaand, OR(USA), 2010/10/13, , 2010.

小原一成, 短期的スロースリップ・深部低周波微動、地震予知連絡会編「地震予知連絡会40年のあゆみ」, 国土地理院, 2009.

小原一成, 独立行政法人防災科学技術研究所、地震予知連絡会編「地震予知連絡会40年のあゆみ」, 国土地理院, 2009.