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

Kaoru Tojo; Keiko Udo

doi:10.2112/SI85-035.1

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

Kaoru Tojo, Keiko Udo

ENG - Civil and Environmental Engineering

Tokyo Gas Co., Ltd.

Research output: Contribution to journal › Article › peer-review

2 Citations (Scopus)

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 language	English
Pages (from-to)	171-175
Number of pages	5
Journal	Journal of Coastal Research
Volume	85
DOIs	https://doi.org/10.2112/SI85-035.1
Publication status	Published - 2018 May 1

Keywords

beach erosion
beach recovery
complex shoreline
ISODATA
tsunami

UN SDGs

This output contributes to the following UN Sustainable Development Goals (SDGs)

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10.2112/SI85-035.1

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

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.",

keywords = "beach erosion, beach recovery, complex shoreline, ISODATA, tsunami",

author = "Kaoru Tojo and Keiko Udo",

note = "Funding Information: The authors would like to thank the Biodiversity Center of Japan for providing coastline change dataset. This research was supported by the Special Project Research of IRIDeS (International Research Institute of Disaster Science, Tohoku University, Japan) and the Social Implementation Program on Climate Change Adaptation Technology (SI-CAT) of MEXT, Japan. Publisher Copyright: {\textcopyright} Coastal Education and Research Foundation, Inc. 2018.",

year = "2018",

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doi = "10.2112/SI85-035.1",

language = "English",

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AU - Tojo, Kaoru

AU - Udo, Keiko

N1 - Funding Information: The authors would like to thank the Biodiversity Center of Japan for providing coastline change dataset. This research was supported by the Special Project Research of IRIDeS (International Research Institute of Disaster Science, Tohoku University, Japan) and the Social Implementation Program on Climate Change Adaptation Technology (SI-CAT) of MEXT, Japan. Publisher Copyright: © Coastal Education and Research Foundation, Inc. 2018.

PY - 2018/5/1

Y1 - 2018/5/1

N2 - 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.

AB - 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.

KW - beach erosion

KW - beach recovery

KW - complex shoreline

KW - ISODATA

KW - tsunami

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DO - 10.2112/SI85-035.1

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VL - 85

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JO - Journal of Coastal Research

JF - Journal of Coastal Research

ER -

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

Abstract

Keywords

UN SDGs

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