Microseismicity around the Nagamachi-Rifu Fault, Miyagi Prefecture, Northeastern Japan
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- YOSHIMOTO Kazuo
- Graduate School of Science, Tohoku University
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- UCHIDA Naoki
- Graduate School of Science, Tohoku University
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- SATO Haruo
- Graduate School of Science, Tohoku University
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- OHTAKE Masakazu
- Graduate School of Science, Tohoku University
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- HIRATA Naoshi
- Earthquake Research Institute, the University of Tokyo
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- OBARA Kazushige
- National Research Institute for Earth Science and Disaster Prevention
Bibliographic Information
- Other Title
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- 長町-利府断層 (宮城県中部) 近傍の微小地震活動
- ナガマチ リフ ダンソウ ミヤギケン チュウブ キンボウ ノ ビショウ ジシン カツドウ
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Abstract
To investigate microseismicity around the Nagamachi-Rifu fault, the B class active reverse fault with a northeast-southwest strike and a northwest dip, Miyagi Prefecture, northeastern Japan, a temporal seismic observation composed of sixteen high-sensitivity stations was carried out for the total period of one year between 1996 and 1998. In spite of high artificial noise in the urban area of Sendai City, we succeeded in obtaining high-quality seismic data by using a DAT continuous recording system. The total number of the earthquakes recorded is 119, of which the smallest one is magnitude -0.5. The depths of the events range between 3 and 13km. Most of hypocenters are concentrated in the northwestern region of the Nagamachi-Rifu fault, while few earthquakes in the southeastern region regardless of our high sensitivity observation. This indicates that these earthquakes occur only in the hanging wall side of this active fault. Focal mechanisms in this region are not necessarily coincident with that of the Nagamachi-Rifu fault. In particular, focal-plane solutions of strike-slip are predominant along the Kagitori-Okubushi line, which is a flexure with a conjugate strike to the Nagamachi-Rifu fault. The spatial pattern of the horizontal crustal strain also changes its characteristics across this line. These results strongly suggest that not only the Nagamachi-Rifu fault but also the Kagitori-Okubushi line may control the seismogenesis of this area.
Journal
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- Zisin (Journal of the Seismological Society of Japan. 2nd ser.)
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Zisin (Journal of the Seismological Society of Japan. 2nd ser.) 52 (4), 407-416, 2000
SEISMOLOGICAL SOCIETY OF JAPAN
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Details 詳細情報について
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- CRID
- 1390001204306990208
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- NII Article ID
- 10004679455
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- NII Book ID
- AN00305741
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- ISSN
- 18839029
- 2186599X
- 00371114
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- NDL BIB ID
- 5341694
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- Data Source
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- JaLC
- NDL
- Crossref
- CiNii Articles
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- Abstract License Flag
- Disallowed