gov.usgs.earthquake.nshmp.gmm

Class BcHydro_2012

java.lang.Object

gov.usgs.earthquake.nshmp.gmm.BcHydro_2012

All Implemented Interfaces:

GroundMotionModel

public abstract class BcHydro_2012
extends Object
implements GroundMotionModel

Abstract implementation of the subduction ground motion model created for BC Hydro, Canada, by Addo, Abrahamson, & Youngs (2012). An update to this implementation is documented in Abrahamson, Gregor, & Addo (2016). This model supports both slab and interface type events.

Note: Direct instantiation of GroundMotionModels is prohibited. Use Gmm.instance(Imt) to retrieve an instance for a desired Imt.

Changes due to Abrahamson et al. (2016) update:

• Added coefficients for 0.02s that are identical to PGA. 0.02s ground motions had previously had been computed via interpolation between 0.01s and 0.05s.
• Slab zTop adjusted from 125 km to 120 km.
• Changed interpolation of the ΔC1 magnitude-scaling break term to log spectral periods and linear values; prior implementation was linear; change affects the following spectral periods: 0.4s, 0.6s (disabled), 0.75s, 1.5s, and 2.5s wherein the ΔC1 value has decreased by 0.01

Implementation notes:

• Treats all sites as forearc; no backarc term is considered.
• zTop is interpreted as hypocentral depth and is only used for slab events; it is limited to 120 km, consistent with other subduction models.
• Only the middle branch of the ΔC1 magnitude-scaling break term for interface events is considered; the ΔC1 term for slab events is fixed at -0.3.
• Support for spectral period 0.01s is provided using the same coefficients as bounding periods PGA and 0.02s.
• Support for spectral periods 0.03s is provided via interpolation of ground motion and sigma of adjacent periods.

Reference: Abrahamson, N., Gregor, N., and Addo, K., 2016, BC Hydro ground motion prediction equations for subduction earthquakes: Earthquake Spectra, v. 32, n. 1, p. 23-44.

doi: 10.1193/051712EQS188MR

Reference: Addo, K., Abrahamson, N., and Youngs, R., (BC Hydro), 2012, Probabilistic seismic hazard analysis (PSHA) model—Ground motion characterization (GMC) model: Report E658, v. 3, November.

Component: Geometric mean of two horizontal components

Author:

Peter Powers

See Also:

Gmm.BCHYDRO_12_INTERFACE, Gmm.BCHYDRO_12_SLAB, Gmm.BCHYDRO_12_INTERFACE_BASIN_AMP, Gmm.BCHYDRO_12_SLAB_BASIN_AMP

Method Summary

Modifier and Type	Method and Description
ScalarGroundMotion	calc(GmmInput in) Compute the scalar ground motion and its standard deviation for the supplied arguments.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

calc

public final ScalarGroundMotion calc(GmmInput in)

Description copied from interface: GroundMotionModel

Compute the scalar ground motion and its standard deviation for the supplied arguments.

Specified by:

calc in interface GroundMotionModel

Parameters:

in - a ground motion model input argument container

Returns:

a scalar ground motion wrapper