Analysis of Beach Recovery after the 2011 Tohoku Earthquake Tsunami Based on Shoreline Extraction by ISODATA

Kaoru Tojo, Keiko Udo

Research output: Contribution to journalArticle

Abstract

The 2011 Tohoku earthquake tsunami caused the disappearance of beaches over a wide area. Understanding of the beach recovery process after the tsunami is important for long-term coastal management. This study aimed to develop a highly accurate method of shoreline extraction using satellite and aerial images and to clarify characteristics of beach recovery by analyzing shoreline changes in the tsunami-affected area. Shorelines extracted by the Iterative Self Organizing Data Analysis Technique (ISODATA) with tidal- and wave-corrections agree well with those obtained from topography measurements. In addition, the shorelines extracted from 406 images from before the tsunami to four years after it at 44 beaches demonstrated the shorelines tended to be recovered at plain coasts and not to be recovered at ria coasts. It is confirmed that the method based on ISODATA is highly accurate and significantly reduces the time and labor.

Original languageEnglish
Pages (from-to)171-175
Number of pages5
JournalJournal of Coastal Research
Volume85
DOIs
Publication statusPublished - 2018 May 1

Keywords

  • ISODATA
  • beach erosion
  • beach recovery
  • complex shoreline
  • tsunami

ASJC Scopus subject areas

  • Ecology
  • Water Science and Technology
  • Earth-Surface Processes

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