## Abstract

Incipient motion formulas, also known as threshold entrainment formulas, Nott’s formulas (after Nott, 2003), or revised Nott’s formulas for initiation of motion, are simple but useful tools that are widely applied for reconstructing magnitudes of high-energy events from their boulder deposits. Since their presentation in 2003, various attempts have been done to improve the quality of the formulas such as the soundness of the concept, the best formulation of the governing forces, and the rationale of the mathematical frame used in their development. In this chapter, a concise description of the formulas of Nott (2003) and significant attempts to improve the formulas are given. Further, the sensitivity of the flow characteristics on the parametric coefficients of the formulas is analyzed in detail. It is found that the significance of the parametric coefficients of the formulas to the minimum flow velocity to initiate the transport of boulder strongly depends on the characteristics and pre-transport environment of the boulder. Potential misuses of the formulas are also exemplified. The numerical insights derived in this chapter will be useful in the application and validation of the formulas.

Original language | English |
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Title of host publication | Geological Records of Tsunamis and Other Extreme Waves |

Publisher | Elsevier |

Pages | 641-659 |

Number of pages | 19 |

ISBN (Electronic) | 9780128156865 |

DOIs | |

Publication status | Published - Jan 1 2020 |

## Keywords

- Boulder
- Entrainment
- Numerical model
- Sensitivity
- Tsunami

## ASJC Scopus subject areas

- General Earth and Planetary Sciences