Bradley 2013

class openquake.hazardlib.gsim.bradley_2013.Bradley2013

Implements GMPE developed by Brendan Bradley for Active Shallow Crust Earthquakes for New Zealand, and published as “A New Zealand-Specific Pseudospectral Acceleration Ground-Motion Prediction Equation for Active Shallow Crustal Earthquakes Based on Foreign Models” (2013, Bulletin of the Seismological Society of America, Volume 103, No. 3, pages 1801-1822).

This model is modified from Chiou and Youngs, 2008 and has been adapted for New Zealand conditions. Specifically, the modifications are related to: 1) small magnitude scaling; 2) scaling of short period ground motion from normal faulting events in volcanic crust; 3) scaling of ground motions on very hard rock sites; 4) anelastic attenuation in the New Zealand crust; 5) consideration of the increates anelastic attenuation in the Taupo Volcanic Zone (not implemented in this model, use Bradley2013Volc)

COEFFS = <openquake.hazardlib.gsim.base.CoeffsTable object>

Coefficient tables are constructed from values in tables 1, 2 and 3 (pages 197, 198 and 199) in Chiou & Youngs,2008. Only Coefficients c1, c1b, c3, cm, c8, cg1, cg2, ctvz are modified by Bradley 2013. Spectral acceleration is defined for damping of 5%, see page 208 (CY08).

DEFINED_FOR_INTENSITY_MEASURE_COMPONENT = 'Average horizontal'

Supported intensity measure component is geometric mean of two horizontal components attr:~openquake.hazardlib.const.IMC.AVERAGE_HORIZONTAL, see abstract page 1801.

DEFINED_FOR_INTENSITY_MEASURE_TYPES = set([<class 'openquake.hazardlib.imt.SA'>, <class 'openquake.hazardlib.imt.PGA'>])

Supported intensity measure types are spectral acceleration, peak ground velocity and peak ground acceleration. Note that PGV is the Chiou & Youngs PGV and has not been modified for New Zealand.

DEFINED_FOR_STANDARD_DEVIATION_TYPES = set(['Total', 'Inter event', 'Intra event'])

Supported standard deviation types are inter-event, intra-event and total, see chapter “Variance model”.

DEFINED_FOR_TECTONIC_REGION_TYPE = 'Active Shallow Crust'

Supported tectonic region type is active shallow crust, see page 1801

REQUIRES_DISTANCES = set(['rx', 'rjb', 'rrup'])

Required distance measures are RRup, Rjb and Rx (all are in eq. 13a).

REQUIRES_RUPTURE_PARAMETERS = set(['rake', 'dip', 'ztor', 'mag'])

Required rupture parameters are magnitude, rake (eq. 13a and 13b), dip (eq. 13a) and ztor (eq. 13a).

REQUIRES_SITES_PARAMETERS = set(['vs30measured', 'z1pt0', 'vs30'])

Required site parameters are Vs30 (eq. 13b), Vs30 measured flag (eq. 20) and Z1.0 (eq. 13b).

get_mean_and_stddevs(sites, rup, dists, imt, stddev_types)

See superclass method for spec of input and result values.

class openquake.hazardlib.gsim.bradley_2013.Bradley2013Volc

Extend Bradley2013 for earthquakes with paths across the Taupo Volcanic Zone (rtvz) that have increased anelastic attenuation.

Implements GMPE developed by Brendan Bradley for Active Shallow Crust Earthquakes for New Zealand, and published as “A New Zealand-Specific Pseudospectral Acceleration Ground-Motion Prediction Equation for Active Shallow Crustal Earthquakes Based on Foreign Models” (2013, Bulletin of the Seismological Society of America, Volume 103, No. 3, pages 1801-1822).

This model is modified from Chiou and Youngs, 2008 and has been adapted for New Zealand conditions. Specifically, the modifications are related to: 1) small magnitude scaling; 2) scaling of short period ground motion from normal faulting events in volcanic crust; 3) scaling of ground motions on very hard rock sites; 4) anelastic attenuation in the New Zealand crust; 5) consideration of the increates anelastic attenuation in the Taupo Volcanic Zone (rtvz is equal to rrup)