Frequency versus tons of oil spilt curve of oil tankers using an enhanced power-law distribution function

  • Tomohiro YuzuiEmail author
  • Fujio Kaneko
Original article


There is a possibility that accidents of oil tankers cause human loss and/or marine environmental pollution. Therefore, it is important to examine safety measures to prevent the accidents or to reduce subsequent damages. “Risk” is an index to quantitatively evaluate the effectiveness of such measures. One of the methods to express the risk is FT (frequency vs. tons of spilt oil) curve. Some approximation functions have been proposed so far by the application of power-law distributions to express exceedance frequency curves of consequence severity, corresponding to FT curve. However, there are some technical issues to be resolved in these approximation functions. Hence, the authors developed approximation functions to express the exceedance frequency curve of consequence severity by applying power-law distributions. In this study, these functions have been modified further to approximate FT curve. It has been found that the present functions nicely reproduce FT curve obtained from historical database. Furthermore, in the application of the present functions, it has been shown that the approximation of FT curve by these functions enables us to identify a volume range of spilt oil with higher risk.


Frequency versus tons of oil spilt (FT) curve Enhanced power-law distribution function Oil tanker Risk analysis 



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Copyright information

© The Japan Society of Naval Architects and Ocean Engineers (JASNAOE) 2019

Authors and Affiliations

  1. 1.National Institute of Maritime, Port and Aviation Technology (MPAT), National Maritime Research Institute (NMRI)MitakaJapan

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