def get_panel_tau_phi(imt, mag):
"""
Returns the inter-event (tau) and intra_event standard deviation (phi)
according to the USGS Sigma Panel recommendations
"""
C = COEFFS_USGS_SIGMA_PANEL[imt]
# Get tau
if mag <= 4.5:
tau = C["t1"]
elif mag <= 5.0:
tau = ITPL(mag, C["t2"], C["t1"], 4.5, 0.5)
elif mag <= 5.5:
tau = ITPL(mag, C["t3"], C["t2"], 5.0, 0.5)
elif mag <= 6.5:
tau = ITPL(mag, C["t4"], C["t3"], 5.5, 1.0)
else:
tau = C["t4"]
# Get phi
if mag <= 5.0:
phi = C["ss_a"]
elif mag <= 6.5:
phi = ITPL(mag, C["ss_b"], C["ss_a"], 5.0, 1.5)
else:
phi = C["ss_b"]
return tau, phi
def get_epri_tau_phi(imt, mag):
"""
Returns the inter-event (tau) and intra_event standard deviation (phi)
according to the updated EPRI (2013) model"""
C = COEFFS_USGS_SIGMA_EPRI[imt]
if mag <= 5.0:
tau = C["tau_M5"]
phi = C["phi_M5"]
elif mag <= 6.0:
tau = ITPL(mag, C["tau_M6"], C["tau_M5"], 5.0, 1.0)
phi = ITPL(mag, C["phi_M6"], C["phi_M5"], 5.0, 1.0)
elif mag <= 7.0:
tau = ITPL(mag, C["tau_M7"], C["tau_M6"], 6.0, 1.0)
phi = ITPL(mag, C["phi_M7"], C["phi_M6"], 6.0, 1.0)
else:
tau = C["tau_M7"]
phi = C["phi_M7"]
return tau, phi