Performance of Countermeasures Against Massive Slope Failures in Sendai City During the 2011 Tohoku Earthquake
Nozomu Yoshida* and Kazue Wakamatsu**,†
*Department of Civil and Environmental Engineering, Tohoku Gakuin University
1-13-1 Chuo, Tagajo, Miyagi 985-8537, Japan
**Department of Civil Engineering, Kanto Gakuin University, Yokohama, Japan
This paper presents a case history of extensive damage due to large-scale slope failure during two successive earthquakes and the positive impact of countermeasures in Midorigaoka, Sendai, Japan. We detail damage during the two earthquakes, postquake countermeasures, and problems encountered during restoration. The area was damaged during the 1978 Miyagiken-oki Earthquake, after which countermeasures were deployed. The most significant damage was at Midorigaoka 1-chome, where 18 houses were demolished and two areas were abandoned. Extensive countermeasures such as a collecting well, landslide prevention piles, and retaining walls were implemented here. In Midorigaoka 3-chome, 14 houses were demolished and two areas were abandoned. Landslide prevention piles were installed and a landslide-controlling dam constructed. Failure was only superficial at Midorigaoka 4-chome, so no heavy remedial work was needed. The Midorigaoka district was hit again by the 2011 Tohoku Earthquake, although no damage was observed at 1-chome. Damage at 3-chome resembled that in the 1978 earthquake. Ground movement of up to 1–2 m was induced at Midorigaoka 4-chome, where approximately 100 houses collapsed and the area itself was forbidden for housing use. The degree of damage during this earthquake depended upon countermeasures adopted after the 1978 earthquake.
-  Sendai City, Locations showing damaged housing lots as of July 31, 2013, http://www.city.sendai.jp/jutaku/_icsFiles/afieldfile/2013/ 09/04/20130731hisaitakuchi5728.pdf [in Japanese, accessed Dec. 1, 2014]
-  Ministory of Land, Infrastracture, Transport and Tourism, Founding of emergency measure to land sliding and failures of housing lots in developed land, http://www.mlit.go.jp/toshi/toshi_tk1_000003.html [in Japanese, accessed Dec. 15, 2011]
-  Disaster Investigation Subcommittee, Report of Earthquake Disaster during the 1968 Tokachi-oki Earthquake, Architectural Institute of Japan, 773pp., 1968 (in Japanese).
-  K. Matsushita, T. Mori, M. Kazama, and S. Sato, “Damage to residential area and its restoration,” Kisoko, Vol.40, No.12, pp. 15-18, 2012 (in Japanese).
-  Sendai City, Data Sendai 2015, http://www.city.sendai.jp/kikaku /seisaku/yoran/data_sendai/pdf/datasendai_all.pdf [in Japanese, accessed Dec. 1, 2015]
-  K. Yoshikawa and Y. Sasaki, “Secular change of ground strength of developed fill ground (an example of “Development M” seven years after the Miyagiken-oki Earthquake),” Research meeting report, Tohoku Branch of Japan Society of Soil Mechanics and Foundation Engineering, pp. 41-16, 1985 (in Japanese).
-  A. Asada, “What Scared Is Not Earthquake But Ground!,” Maruzen, Tokyo, 174pp., 2006 (in Japanese).
-  Sendai City, Report, the Technical Special Committee in Advisory Board for Conservation of Housing Land, Sendai City, 2012 (in Japanese).
-  K. Shibuya, “Revision of Housing Land Development Regulation Act. – prevention of developed land against earthquake –,” J. of Geography, Vol.116, No.3&4, pp. 511-515, 2007 (in Japanese).
-  A. Asada, “An Empirical Approach for Predicting and Reducing Earthquake Damage, A Case Study on Damage to Housing Development during the 1978 Miyagiken-oki Earthquake,” Report, Tohoku Institute of Technology, 83pp., 2006 (in Japanese).
-  K. Kadota, S. Sato, S. Mishima, and M. Hiruma, “Restoration and aseismic countermeasures of damaged developed land in Sendai City during the Tohoku earthquake,” Geotechnical Engineering Magazine, Vol.61, No.4, pp. 26-29, 2013 (in Japanese).
-  Miyagi Prefecture (Ed.), “Lessons from ’78 Miyagiken-oki Earthquake – Reality and Agenda,” Hobundo, 406pp., 1980 (in Japanese).
-  Investigation Committee of the 1978 Miyagiken-oki Earthquake, General Report on the 1978 Miyagiken-oki Earthquake, Tohoku Branch of the Japan Society of Civil Engineering, 504pp., 1980 (in Japanese).
-  M. Kobayashi, H. Sunaga, and S. Ichikawa, “Special report on 1978 Miyagiken-oki Earthquake on Topographical Condition and Ground Failure,” Research Coordination Bureau, Science and Technology Agency, pp. 131-173, 1980 (in Japanese).
-  Kahoku Shinpo (Ed.), “Record and Lessons Learned during the ’78 Miyagiken-oki Earthquake,” Kahoku Shinpo, 48pp., 1978 (in Japanese).
-  T. Mori, Y. Tobita, and T. Okimura, “Damages of hillside embankments in Sendai City during the 2011 off the Pacific Coast of Tohoku Earthquake,” Soils and Foundations, Vol.52, No.5, pp. 910-928, 2012.
-  T. Okimura, Y. Nabeshima, H. Okada, and S. Nomani, “Report on Damage to Residential Area in the Sendai City and Vicinity during the Off the Pacific Coast of Tohoku Earthquake,” Liaison Committee of Japanese Geotechnical Society, 33pp., 2011 (in Japanese).
-  Sendai City, The Material for the 29th Advisory Board for Conservation of Housing Land, http://www.city.sendai.jp/fuzoku /1197681_2699.html, 2011 [in Japanese, accessed Dec. 1, 2015]
-  Sendai City, Report, the Technical Special Committee in Advisory Board for Conservation of Housing Land, Sendai City, 2013 (in Japanese).
-  Kahoku Shinpo, Kahoku Shinpo Newspaper, 2013.1.23 (in Japanese).