Object-based image analysis for mapping earthquake-induced liquefaction ejecta in Christchurch, New Zealand

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• 作者：Justin Morgenroth ; Matthew W. Hughes ; Misko Cubrinovski
• 刊名：Natural Hazards
• 出版年：2016
• 出版时间：June 2016
• 年：2016
• 卷：82
• 期：2
• 页码：763-775
• 全文大小：3,577 KB
• 刊物类别：Earth and Environmental Science
• 刊物主题：Earth sciences
  Hydrogeology
  Geophysics and Geodesy
  Geotechnical Engineering
  Civil Engineering
  Environmental Management
  
• 出版者：Springer Netherlands
• ISSN：1573-0840
• 卷排序：82

文摘

Earthquake-induced liquefaction poses significant risks to the urban environment and infrastructure lifelines. Following significant liquefaction, surface ejecta can impact facilities, impede transportation systems and complicate emergency response. Few studies have applied remote sensing technologies to map the spatial extent of liquefaction ejecta across entire affected urban areas. Here, we use object-based image analysis (OBIA) of aerial photography and light detection and ranging (LiDAR) data to map the occurrence of liquefaction ejecta following the 22 February 2011 earthquake in Christchurch, New Zealand. The OBIA achieved an 81.8 % overall accuracy for an initial classification that identified the presence or absence of liquefaction ejecta. The overall accuracy decreased to 74.8 % when attempting to distinguish between liquefaction ejecta deposited over differing land covers; this was due to the spectral and textural variation amongst these being insufficiently unique. We suggest that OBIA is useful for efficient determination of the spatial extent of post-disaster liquefaction ejecta in urban environments. This is significant for its potential to support emergency response and clean-up operations as well as longer-term ground performance and infrastructure impact assessments.KeywordsAccuracy assessmentAerial laser scanningCanterbury earthquake sequenceLand cover classificationLiDARRemote sensing