### Abstract

Equations for the prediction of response spectral ordinates invariably include magnitude, distance and site classification as independent variables. A few equations also include style-offaulting as a fourth variable, although this has an almost negligible effect on the standard deviation of the equation. Nonetheless, style-of-faulting is a useful parameter to include in ground-motion prediction equations since the rupture mechanism of future earthquakes in a particular seismic source zone can usually be defined with some confidence. Current equations including style-of-faulting use different schemes to classify fault ruptures into various categories, which leads to uncertainty and ambiguity regarding the nature and extent of the effect of focal mechanism on ground motions. European equations for spectral ordinates do not currently include style-of-faulting factors, and seismic hazard assessments in Europe often combine, in logic-tree formulations, these equations with those from western North America that do include style-of-faulting coefficients. In this article, a simple scheme is provided to allow style-of-faulting adjustments to be made for those equations that do not include coefficients for rupture mechanism, so that style-of-faulting can be fully incorporated into the hazard calculations. This also considers the case of normal fault ruptures, not modelled in any of the current Californian equations, but which are the dominant mechanism in many parts of Europe. The scheme is validated by performing new regressions on a widely used European attenuation relationship with additional terms for style-of-faulting.

Language | English |
---|---|

Pages | 171-203 |

Number of pages | 33 |

Journal | Bulletin of Earthquake Engineering |

Volume | 1 |

Issue number | 2 |

DOIs | |

Publication status | Published - May 2003 |

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### Keywords

- attenuation relations
- fault rupture mechanism
- logic-tree analysis
- seismic hazard assessment

### Cite this

*Bulletin of Earthquake Engineering*,

*1*(2), 171-203. https://doi.org/10.1023/A:1026323123154

}

*Bulletin of Earthquake Engineering*, vol. 1, no. 2, pp. 171-203. https://doi.org/10.1023/A:1026323123154

**Style-of-faulting in ground-motion prediction equations.** / Bommer, Julian J.; Douglas, John; Strasser, Fleur O.

Research output: Contribution to journal › Article

TY - JOUR

T1 - Style-of-faulting in ground-motion prediction equations

AU - Bommer, Julian J.

AU - Douglas, John

AU - Strasser, Fleur O.

PY - 2003/5

Y1 - 2003/5

N2 - Equations for the prediction of response spectral ordinates invariably include magnitude, distance and site classification as independent variables. A few equations also include style-offaulting as a fourth variable, although this has an almost negligible effect on the standard deviation of the equation. Nonetheless, style-of-faulting is a useful parameter to include in ground-motion prediction equations since the rupture mechanism of future earthquakes in a particular seismic source zone can usually be defined with some confidence. Current equations including style-of-faulting use different schemes to classify fault ruptures into various categories, which leads to uncertainty and ambiguity regarding the nature and extent of the effect of focal mechanism on ground motions. European equations for spectral ordinates do not currently include style-of-faulting factors, and seismic hazard assessments in Europe often combine, in logic-tree formulations, these equations with those from western North America that do include style-of-faulting coefficients. In this article, a simple scheme is provided to allow style-of-faulting adjustments to be made for those equations that do not include coefficients for rupture mechanism, so that style-of-faulting can be fully incorporated into the hazard calculations. This also considers the case of normal fault ruptures, not modelled in any of the current Californian equations, but which are the dominant mechanism in many parts of Europe. The scheme is validated by performing new regressions on a widely used European attenuation relationship with additional terms for style-of-faulting.

AB - Equations for the prediction of response spectral ordinates invariably include magnitude, distance and site classification as independent variables. A few equations also include style-offaulting as a fourth variable, although this has an almost negligible effect on the standard deviation of the equation. Nonetheless, style-of-faulting is a useful parameter to include in ground-motion prediction equations since the rupture mechanism of future earthquakes in a particular seismic source zone can usually be defined with some confidence. Current equations including style-of-faulting use different schemes to classify fault ruptures into various categories, which leads to uncertainty and ambiguity regarding the nature and extent of the effect of focal mechanism on ground motions. European equations for spectral ordinates do not currently include style-of-faulting factors, and seismic hazard assessments in Europe often combine, in logic-tree formulations, these equations with those from western North America that do include style-of-faulting coefficients. In this article, a simple scheme is provided to allow style-of-faulting adjustments to be made for those equations that do not include coefficients for rupture mechanism, so that style-of-faulting can be fully incorporated into the hazard calculations. This also considers the case of normal fault ruptures, not modelled in any of the current Californian equations, but which are the dominant mechanism in many parts of Europe. The scheme is validated by performing new regressions on a widely used European attenuation relationship with additional terms for style-of-faulting.

KW - attenuation relations

KW - fault rupture mechanism

KW - logic-tree analysis

KW - seismic hazard assessment

UR - http://www.scopus.com/inward/record.url?scp=4944248222&partnerID=8YFLogxK

U2 - 10.1023/A:1026323123154

DO - 10.1023/A:1026323123154

M3 - Article

VL - 1

SP - 171

EP - 203

JO - Bulletin of Earthquake Engineering

T2 - Bulletin of Earthquake Engineering

JF - Bulletin of Earthquake Engineering

SN - 1570-761X

IS - 2

ER -