Coastal and Estuarine Morphology Changes Induced by the 2011 Great East Japan Earthquake Tsunami

The 2011 Great East Japan Earthquake that occurred on March 11, 2011, had magnitude of 9.0 on the Richter Scale with the epicenter approximately 70 km east of the Oshika Peninsula in Miyagi Prefecture. This earthquake triggered terrible tsunami waves which hit the coast of Japan and propagated around the Pacific Ocean. The earthquake and tsunami caused extensive and severe infrastructural damage, such as damages of coastal protection structures and buildings, and significantly changed coastal and river morphology. This paper presents tsunami-induced coastal and estuarine morphology changes in Miyagi Prefecture, Japan, and subsequent recovery process in each study area. On sandy coasts, discontinuous coastal protection is likely to be severely damaged, resulting in serious erosion in the surrounding sandy coast. Furthermore, severe breaching was observed on sandy coasts where formerly river mouth was located, due to strong return flow from the catchment area. The restoration process of the coast and estuaries is highly dependent on sediment supply availability in the surrounding area.

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