Skip to Content

CY08 Sub-Functions {nga}

CY08 Sub-Functions
Package: 
nga
Version: 
1.4-1

Description

The sub-functions needed to estimate ground motions using the Chiou & Youngs NGA model. These functions are called by the main function used for calculations, Sa.cy.

Usage

LnYref.cy(M, Rrup, Rjb, Rx, Ztor, dip, Frv, Fnm, Fhw, AS, T)
NL.cy(Yref, Vs30, T)
Sigma.cy(M, Yref, Vs30, VsFlag, AS, T)
Tau.cy(M, T)
SigmaTot.cy(M, Yref, Vs30, VsFlag, AS, T)
SaMedian.cy(M, Rjb, Rrup, Rx, Ztor, Frv, Fnm, AS, Fhw, dip, Vs30, Z1.0, T)

Arguments

M
Moment magnitude of earthquake.
Rjb
Horizontal distance to the surface projection of the rupture plane; Joyner-Boore distance (km).
Rrup
Closest distance to the rupture plane; rupture distance (km).
Rx
Horizontal distance to the surface projection of the top edge of the rupture plane, measured perpendicular to the strike; site coordinate (km).
Ztor
Depth to top of rupture (km).
Frv
Reverse style-of-faulting flag; equal to 1 for reverse faulting (30 <= rake <= 150 deg), and 0 otherwise.
Fnm
Normal style-of-faulting flag; equal to 1 for normal faulting (-120 <= rake <= -60 deg), and 0 otherwise.
AS
Aftershock flag; equal to 1 for aftershocks and 0 for mainshocks.
Fhw
Hanging wall flag; equal to 1 for sites on the hanging wall side of the fault (Rx >= 0) and 0 otherwise.
dip
Fault dip angle (deg).
Vs30
Time-averaged shear wave velocity over a subsurface depth of 30 meters (m/s).
VsFlag
Flag variable indicating how Vs30 is obtained; equal to 1 if Vs30 is measured, and 0 if Vs30 is estimated or inferred.
Z1.0
Depth to Vs = 1.0 km/s (m).
Yref
Median ground motion for the reference rock site condition (g).
T
Spectral period (sec). Use 0 for PGA and -1 for PGV.

Details

LnYref.cy
Median ground motion on reference rock site (Eqn 13a of Chiou and Youngs (2008)).
NL.cy
Nonlinear site response term (Eqns 10 and 21).
Sigma.cy
Intra-event standard deviation (Eqn 20).
Tau.cy
Inter-event standard deviation (Eqn 19).
SigmaTot.cy
Total standard deviation (Eqn 21).
SaMedian.cy
Median estimate of ground motion, with site response (Eqn 13b).

Values

Returns values of the sub-functions for the Chiou & Youngs NGA model. The outputs of the functions are in log space, with the exception of SaMedian.cy, which outputs values in g (for Sa and PGA) or cm/s (for PGV).

References

Chiou, B. S.-J., and R. R. Youngs (2008). An NGA Model for the Average Horizontal Component of Peak Ground Motion and Response Spectra. Earthquake Spectra 24, 173--215.

See Also

coefs, coefs.t.cy, periods.cy, Sa.cy, Sa.nga.

Author(s)

James Kaklamanos and Eric M. Thompson

Documentation reproduced from package nga, version 1.4-1. License: GPL-2