II Evaluation of Fragility Functions for Tsunami Damage in Coastal District in Natori City, Miyagi Prefecture and Mitigation Effects of Coastal Dune Yasuo NIHEI, Toshiaki MAEKAWA, Rika OHSHIMA and Maimi YANAGISAWA To clarify the structural damage in Sendai Plain along sandy coasts due to huge tsunami attack on 11 March 2011 and its countermeasure, in the present study, we conducted field survey for structural damage and tsunami height in coastal district of Natori City, Sendai Plain in which an artificial sand dune with the height of about 9 m is located. The measured results indicate that devastated buildings were concentrated in coastal district in which a distance from the shoreline was less than 1 km. The fragility functions for tsunami damage in this site were evaluated using the measured inundation depth. It is also found that the sand dune has an effect on reduction of structural damages due to tsunami inundation. 1. 2011 3 11 9.0 4 1000 GPS 6m 2011 20mMori, 2012 Ogasawara 2012 5km Gokon Koshimura 2012 Koshimura 2009 2. 1 1 1 3
2 1 GoogleEarth 9.1 T.P.m 200m 4 T.P.m Danielsen 2005 Tanaka 2007 2 2 2007 2 4 5253 RC Static GPS FlexPak NovAtel VRS RTK-GPS R4 Trimble DISTO TM D5 Leica 2 RTK-GPS 2011/5/10 12 6/11 12 1 3. 1 3 4 1km
3 RC 1.5 3km 2 4 RC 532 57 88 600m RC 4 RC 500m 5 500m 2m RC 2m 3 5
500m 200m 0.5km 8m 1.5km 3m 3km 0.5m 0.5km 100 1.5km 202.5km 0 1km 100 2m 2km 50 1m2.5km 20 5m 1km 2 5m 1 2km 2m 6 0.5m 3m 4 5 4 3 7 5 6 7 3
0.5m 3m 4 8 9.1 T.P.m9-10m 7 8 0.23km 1km 2012 4. 5000 1 1km 1.5 3km 2 RC RC 2m 3 2011 Static GPS 2011 23 2011 Vol.50 No.4 pp.3-64 2007 2006 Vol.54 No.2 pp.861-865 2012 B2Vol.59 Danielsen, F., M. K. S?rensen, M. F. Olwig, V. Selvam, F. Parish, N. D. Burgess, T. Hiraishi, V. M. Karunagaran, M. S. Rasmussen, L. B. Hansen, A. Quarto and N. Suryadiputra (2005): The Asian tsunami: a protective role for coastal vegetation, Science, Vol. 310, 643p. Gokon, H. and S. Koshimura (2012): Mapping of building damage of the 2011 Tohoku Earthquake Tsunami in Miyagi Prefecture, Coastal Engineering Journal, Vol.54, No.1, 1250006 (12pages). Koshimura, S., T. Oie, H. Yanagisawa and F. Imamura (2009): Developing fragility functions for tsunami damage estimation using numerical model and post-tsunami data from Banda Aceh, Indonesia, Coastal Engineering Journal, Vol.51, No.3, pp.243-273. Mori, N., T. Takahashi and The 2011 Tohoku Earthquake Tsunami Joint Survey Group (2012): Nationwide post event survey and analysis of the 2011 Tohoku earthquake tsunami, Coastal engineering Journal, Vol.54, No.1, 1250001 (27pages. Ogasawara, T., Y. Matsubayashi, S. Sakai and T. Yasuda (2012): Characteristics of the 2011Tohoku earthquake and tsunami and its impact on the northern Iwate coast, Coastal Engineering Journal, Vol.54, No.1, 1250003 (16pages). Tanaka, N., Y. Sasaki, M. I. M. Mowjood, K. B. S. N. Jinadasa and S. Homchuen (2007): Coastal vegetation structures and their functions in tsunami protection: experience of the recent Indian Ocean tsunami, Landscape and Ecological Engineering, Vol.3, No.1, pp.33-45.