Serious erosion of the southern Sendai Coast due to the 2011 tohoku earthquake tsunami and its recovery process

K. Udo, Y. Takeda, M. Takamura, A. Mano

    Research output: Chapter in Book/Report/Conference proceedingChapter

    10 Citations (Scopus)

    Abstract

    We investigate morphology change of the southern Sendai Coast due to the 2011 Tsunami by analyzing topography and aerial images before and after the tsunami. The results show the characteristics such as erosion in the longshore direction behind seawalls, landward sediment transport during tsunami runup, seaward sediment transport from shore during backwash especially through crevasses of the seawalls, and coastal stabilization by coastal structures such as seawalls, breakwaters and headlands. At the seriously eroded Yamamoto Coast, more than half of the total amount of eroded shore sand above sea level was estimated to be transported seaward due to backwash. After 1 year from the tsunami, the eroded coasts were recovered to form pocket beaches. After another year, the coastal morphology had not changed apparently but seawalls started to be reconstructed. At present, after 3 years from the tsunami, the seawalls with a height of 7.2 m have been reconstructed along the coast. With the reconstruction, the foundation ground of the seawalls has been recovered, but the eroded beaches still remain disappeared. The coast act in Japan was established in 1956 to protect the coast from disasters, and amended in 1999 to also preserve both the coastal environment and its utilization. From the perspective of long-term coastal management, it is strongly required to consider the vision of the future coast.

    Original languageEnglish
    Title of host publicationAdvances in Natural and Technological Hazards Research
    PublisherSpringer Netherlands
    Pages225-236
    Number of pages12
    DOIs
    Publication statusPublished - 2015

    Publication series

    NameAdvances in Natural and Technological Hazards Research
    Volume44
    ISSN (Print)1878-9897
    ISSN (Electronic)2213-6959

    Keywords

    • Airborne laser scanning data
    • Bathymetry data
    • Beach morphology
    • Coastal structure
    • Ecosystems

    ASJC Scopus subject areas

    • Global and Planetary Change
    • Geography, Planning and Development
    • Economic Geology
    • Computers in Earth Sciences
    • Management, Monitoring, Policy and Law

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