Chiou & Youngs (2006) Attenuation Relationship

This Attenuation Relationship, which is one of the so-called NGA Models, is described in a Report by Chiou and Youngs (2006).

Supported Intensity Measure Types (IMTs):

• Peak Ground Acceleration (PGA)
• Spectral Acceleration (SA) - 5% damped at the following periods: 0.01, 0.02, 0.022, 0.025, 0.029, 0.03, 0.032, 0.035, 0.036, 0.04, 0.042, 0.044, 0.045, 0.046, 0.048, 0.05, 0.055, 0.06, 0.065, 0.067, 0.07, 0.075, 0.08, 0.085, 0.09, 0.095, 0.1, 0.11, 0.12, 0.13, 0.133, 0.14, 0.15, 0.16, 0.17, 0.18, 0.19, 0.2, 0.22, 0.24, 0.25, 0.26, 0.28, 0.29, 0.3, 0.32, 0.34, 0.35, 0.36, 0.38, 0.4, 0.42, 0.44, 0.45, 0.46, 0.48, 0.5, 0.55, 0.6, 0.65, 0.667, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, 2.2, 2.4, 2.5, 2.6, 2.8, 3, 3.2, 3.4, 3.5, 3.6, 3.8, 4, 4.2, 4.4, 4.6, 4.8, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, and 10 seconds.

Model Details:

We use a (distRup-distJB)/distRup parameter rather than the DistanceJB parameter recommended in their documentation. The reason is for our Attenuation Relationship Plotter, where one can plot intensity-measure levels as a function of one parameter while holding the others constant (the classic attenuation relationship curve plot). It makes no sense to hold DistanceJB constant while allowing DistanceRup to vary, whereas it makes more sense to hold (distRup-distJB)/distRup constant in this situation. Rest assured, this does not change how the calculations are done.

More details can be found in their documentation.