ShakeMap (2003)


This Attenuation Relationship is based on the model used by the USGS ShakeMap group in 2003.



Supported Intensity Measure Types (IMTs): 
SA damping (5%) at the following periods:
  • 0.0
  • 0.3
  • 1.0
  • 3.0
Required Parameters: 
Earthquake Rupture
Model Details: 

This is a hybrid of Boore, Joyner, & Fumal (1997) and the low- magnitude regression developed by Vincent Quitoriano (where the former is used above mag=5.5, the latter is used below 5.0 and a linear-ramp average is used in between). However, rather than using Vs30 as the site paremeter, this uses the Wills et al. (2000, Bull. Seism. Soc. Am., 90, S187-S208) classification scheme and the nonlinear amplification factors of Borcherdt (1994, Earthquake Spectra, 10, 617-654). There is very little written documentation of this relationship. It was therefore composed by Ned Field based on numerous queries to David Wald, Vincent Quitoriano, and Bruce Worden. This model was verified against their calculations.