def quarter_wavelength_average(self):
"""
Compute quarter-wavelength parameters (velocity and density)
and store them into the site database.
"""
self._check_frequency()
for mod in self.model:
# Compute average velocity
qwl_par = _avg.quarter_wavelength_average(mod.geo['hl'],
mod.geo['vs'],
mod.geo['dn'], self.freq)
mod.eng['qwl'] = {}
mod.eng['qwl']['z'] = _ut.a_round(qwl_par[0], DECIMALS)
mod.eng['qwl']['vs'] = _ut.a_round(qwl_par[1], DECIMALS)
mod.eng['qwl']['dn'] = _ut.a_round(qwl_par[2], DECIMALS)
# Perform statistics (log-normal)
self.mean.eng['qwl'] = {}
for key in ['z', 'vs', 'dn']:
data = [mod.eng['qwl'][key] for mod in self.model]
mn, sd = _ut.log_stat(data)
self.mean.eng['qwl'][key] = (_ut.a_round(mn, DECIMALS),
_ut.a_round(sd, DECIMALS))
def traveltime_velocity(self, depth=30.):
"""
Compute and store travel-time average velocity at a given depth.
Multiple depths are also allowed (as list). Default is Vs30.
:param float or list depth:
calculation depth
"""
if not isinstance(depth, list):
depth = [depth]
for mod in self.model:
mod.eng['vsz'] = {}
for z in depth:
vz = _avg.traveltime_velocity(mod.geo['hl'],
mod.geo['vs'],
depth=z)
mod.eng['vsz'][z] = _ut.a_round(vz, DECIMALS)
# Perform statistics (log-normal)
self.mean.eng['vsz'] = {}
for z in depth:
data = [mod.eng['vsz'][z] for mod in self.model]
mn, sd = _ut.log_stat(data)
self.mean.eng['vsz'][z] = (_ut.a_round(mn, DECIMALS),
_ut.a_round(sd, DECIMALS))
def attenuation_decay(self):
"""
Compute the frequency-dependent attenuation function
for a given site Kappa (0).
"""
self._check_frequency()
for mod in self.model:
# Compute attenuation decay
att_fun = _amp.attenuation_decay(self.freq, mod.eng['kappa'])
mod.amp['kappa'] = _ut.a_round(att_fun, DECIMALS)
# Perform statistics (log-normal)
data = [mod.amp['kappa'] for mod in self.model]
mn, sd = _ut.log_stat(data)
self.mean.amp['kappa'] = (_ut.a_round(mn, DECIMALS),
_ut.a_round(sd, DECIMALS))
def quarter_wavelength_amplification(self,
vs_ref=[],
dn_ref=[],
inc_ang=0.):
"""
Compute the amplification as impedance contrast of
quarter-wavelength parameters. Aribitrary reference
can be provided, otherwise the last layer of the model
is used. Angle of incidence is optional.
:param float or numpy.array ref_vs:
lowermost (reference) shear-wave velocity in m/s
:param float or numpy.array ref_dn:
lowermost (reference) density in kg/m3
:param float inc_ang:
angle of incidence in degrees, relative to the vertical
(default is vertical incidence)
"""
for mod in self.model:
if _ut.is_empty(vs_ref):
vs_ref = mod.geo['vs'][-1]
if _ut.is_empty(dn_ref):
dn_ref = mod.geo['dn'][-1]
qwl_amp = _amp.impedance_amplification(mod.eng['qwl']['vs'],
mod.eng['qwl']['dn'],
vs_ref, dn_ref, inc_ang)
mod.amp['qwl'] = _ut.a_round(qwl_amp, DECIMALS)
# Perform statistics (log-normal)
data = [mod.amp['qwl'] for mod in self.model]
mn, sd = _ut.log_stat(data)
self.mean.amp['qwl'] = (_ut.a_round(mn, DECIMALS),
_ut.a_round(sd, DECIMALS))
def compute_site_kappa(self, depth=[]):
"""
Compute the Kappa parameter directly from the site model
using harmonic averaging. Caculation depth can be speficied,
otherwise the depth of the last layer interface is used.
:param float depth:
averaging depth in meters (optional)
"""
for mod in self.model:
# Compute kappa attenuation
kappa = _avg.compute_site_kappa(mod.geo['hl'], mod.geo['vs'],
mod.geo['qs'], depth)
mod.eng['kappa'] = _ut.a_round(kappa, DECIMALS)
# Perform statistics (normal)
data = [mod.eng['kappa'] for mod in self.model]
mn, sd = _ut.lin_stat(data)
self.mean.eng['kappa'] = (_ut.a_round(mn, DECIMALS),
_ut.a_round(sd, DECIMALS))