Attenuation Relationship

Campbell & Bozorgnia (2003) Attenuation Relationship

This Attenuation Relationship was published by Campbell & Bozorgnia (2003, Bull. Seism. Soc. Am., vol 93, num 1, pp 314-331).

Supported Intensity Measure Types (IMTs):

Peak Ground Acceleration (PGA)
Spectral Acceleration (SA) - 5% damped at the following periods: 0.0, 0.05, 0.075, 0.1, 0.15, 0.2, 0.3, 0.4, 0.5, 0.75, 1.0, 1.5, 2.0, 3.0, and 4.0.

Independent Parameters (used to compute exceedance probabilties):

Earthquake Rupture Related Parameters:

Magnitude
Fault Type (Strike Slip or Normal, Thrust (dip<45), Reverse (dip>45), Reverse or Thrust, or Unknown)

Site Related Parameters:

Site Type (Firm Soil, Very Firm Soil, Soft Rock, Firm Rock, Generic Soil, Generic Rock, or NEHRP BC)

Propagation-Effect Related Parameters:

DistanceSeis
Hanging Wall Parameter (1.0 if site is within surface projection of rupture, tapering (linearly) to 0.0 at 5 km beyond)

Other Parameters:

Component (Average Horizontal or Vertical)
Standard Deviation Type (Total (Mag Dependent), Total (PGA Dependent), or Zero)
Sigma Truncation (and Sigma Truncation Level)

Model Details:

The mean calculation for the site class "BC Boundary" is only approximate at 0.05- and 0.075-second periods (because "bv" is not available from BJF_1997 at those periods, so values were linearly interpolated between 0 and 0.1 seconds) and at 3- and 4-seconds ("bv" not available from BJF_1997 above 2 seconds, so value at 2-seconds was applied). See the publication referenced above for more details.