def momentrateFromStrainRateBarba(poly, strain_in, regime):
"""Compute seismic moment rate from Barba strain rate data set.
Input:
poly Area zone geometry as Shapely polygon
strain_in Strain rate dataset as list of lists
[ [lon, lat, value], ...]
regime Dict of Shapely multipolygons for each deformation regime
Currently only Continental (C) and Ridge-transform (R)
implemented
{'C': Multipolygon, 'R': Multipolygon}
Output:
momentrate moment rate computed from strain rate summed
over area zone
"""
momentrate = 0.0
for (lon, lat, value) in strain_in:
# make Shapely point from lon, lat
point = shapely.geometry.Point((lon, lat))
# check if in area zone polygon
# if positive, sum up strain rate contribution
if poly.intersects(point) and value > 0.0:
# get deformation regime
regime_key = strain.tectonicRegimeForPoint(point, regime)
# if point not in one of the tectonic regions, use value for
# crustal
if regime_key not in (strain.DEFORMATION_REGIME_KEY_C,
strain.DEFORMATION_REGIME_KEY_R):
regime_key = strain.DEFORMATION_REGIME_KEY_C
# select value for coupled thickness (cz):
# if crustal, use value of Continental Transform Fault
# if ridge-transform: use value of Oceanic Transform Fault
# unit: km
if regime_key == strain.DEFORMATION_REGIME_KEY_C:
cz = strain.BIRD_SEISMICITY_PARAMETERS[\
strain.DEFORMATION_REGIME_KEY_CTF]['cz']
else:
cz = strain.BIRD_SEISMICITY_PARAMETERS[\
strain.DEFORMATION_REGIME_KEY_OTF]['cz']
momentrate += (cz * value)
# Bird & Liu eq. 7B
# Note: unit of values in Barba dataset is s^-1
# computed strain rate has unit
# km * Pa / s = 1000 m * N / (m^2 * s) = 1000 (Nm/s) per m^2
# TODO(fab): double-check this !!
# convert to strain rate per square kilometre: multiply with 10^-6
# return 1000 * cz * SHEAR_MODULUS * strainrate * 1.0e-6
return 1000 * SHEAR_MODULUS * momentrate
def momentrateFromStrainRateBarba(poly, strain_in, regime):
"""Compute seismic moment rate from Barba strain rate data set.
Input:
poly Area zone geometry as Shapely polygon
strain_in Strain rate dataset as list of lists
[ [lon, lat, value], ...]
regime Dict of Shapely multipolygons for each deformation regime
Currently only Continental (C) and Ridge-transform (R)
implemented
{'C': Multipolygon, 'R': Multipolygon}
Output:
momentrate moment rate computed from strain rate summed
over area zone
"""
momentrate = 0.0
for (lon, lat, value) in strain_in:
# make Shapely point from lon, lat
point = shapely.geometry.Point((lon, lat))
# check if in area zone polygon
# if positive, sum up strain rate contribution
if poly.intersects(point) and value > 0.0:
# get deformation regime
regime_key = strain.tectonicRegimeForPoint(point, regime)
# if point not in one of the tectonic regions, use value for
# crustal
if regime_key not in (strain.DEFORMATION_REGIME_KEY_C,
strain.DEFORMATION_REGIME_KEY_R):
regime_key = strain.DEFORMATION_REGIME_KEY_C
# select value for coupled thickness (cz):
# if crustal, use value of Continental Transform Fault
# if ridge-transform: use value of Oceanic Transform Fault
# unit: km
if regime_key == strain.DEFORMATION_REGIME_KEY_C:
cz = strain.BIRD_SEISMICITY_PARAMETERS[\
strain.DEFORMATION_REGIME_KEY_CTF]['cz']
else:
cz = strain.BIRD_SEISMICITY_PARAMETERS[\
strain.DEFORMATION_REGIME_KEY_OTF]['cz']
momentrate += (cz * value)
# Bird & Liu eq. 7B
# Note: unit of values in Barba dataset is s^-1
# computed strain rate has unit
# km * Pa / s = 1000 m * N / (m^2 * s) = 1000 (Nm/s) per m^2
# TODO(fab): double-check this !!
# convert to strain rate per square kilometre: multiply with 10^-6
# return 1000 * cz * SHEAR_MODULUS * strainrate * 1.0e-6
return 1000 * SHEAR_MODULUS * momentrate
def momentrateFromStrainRateBird(poly, strain_in, regime):
"""Compute seismic moment rate from Bird strain rate data set.
Input:
poly Area zone geometry as Shapely polygon
strain_in Strain rate dataset as list of lists
[ [lat, lon, exx, eyy, exy], ...]
regime Dict of Shapely multipolygons for each deformation regime
Currently only Continental (C) and Ridge-transform (R)
implemented
{'C': Multipolygon, 'R': Multipolygon}
Output:
momentrate moment rate computed from strain rate summed
over area zone
"""
momentrate = 0.0
for (lat, lon, exx, eyy, exy) in strain_in:
# make Shapely point from lon, lat
point = shapely.geometry.Point((lon, lat))
# check if in area zone polygon
# TODO(fab): small area zones that do not include a strain rate
# grid node
if poly.intersects(point):
# get deformation regime
regime_key = strain.tectonicRegimeForPoint(point, regime)
# select values for cz and mc
if regime_key not in (strain.DEFORMATION_REGIME_KEY_C,
strain.DEFORMATION_REGIME_KEY_R):
# point not in available regimes, don't evaluate contribution
# from this point
continue
else:
(e1, e2, e3, e1h, e2h, err) = \
strain.strainRateComponentsFromDataset((exx, eyy, exy))
if regime_key == strain.DEFORMATION_REGIME_KEY_C:
# continental regime
if (
err <= strain.BIRD_CONTINENTAL_REGIME_COMPARISON_FACTOR * e2h \
and err >= strain.BIRD_CONTINENTAL_REGIME_COMPARISON_FACTOR * e1h):
# strike-slip faulting dominates
parameter_key = strain.DEFORMATION_REGIME_KEY_CTF
elif \
err > strain.BIRD_CONTINENTAL_REGIME_COMPARISON_FACTOR * e2h:
# thrust faulting dominates
parameter_key = strain.DEFORMATION_REGIME_KEY_CCB
else:
# normal faulting dominates
parameter_key = strain.DEFORMATION_REGIME_KEY_CRB
elif regime_key == strain.DEFORMATION_REGIME_KEY_R:
# ridge-transform regime
if e1h >= 0.0:
parameter_key = strain.DEFORMATION_REGIME_KEY_OSR
elif e2h < 0.0:
parameter_key = strain.DEFORMATION_REGIME_KEY_OCB
elif (e1h * e2h < 0.0 and (e1h + e2h) >= 0.0):
parameter_key = strain.DEFORMATION_REGIME_KEY_OTF
elif (e1h * e2h < 0.0 and (e1h + e2h) < 0.0):
parameter_key = strain.DEFORMATION_REGIME_KEY_OCB
else:
# never get here
raise RuntimeError, \
"Unexpected case in ridge-transform regime"
# TODO(fab): criterion for not adding contribution
cz = strain.BIRD_SEISMICITY_PARAMETERS[parameter_key]['cz']
if e2 < 0:
momentrate += (2 * cz * e3)
else:
momentrate += (2 * cz * -e1)
# convert original unit of [10^-9 yr^-1] to [s^-1]
return 1000 * SHEAR_MODULUS * 1.0e-9 * momentrate * (60 * 60 * 24 * 365.25)
def momentrateFromStrainRateBird(poly, strain_in, regime):
"""Compute seismic moment rate from Bird strain rate data set.
Input:
poly Area zone geometry as Shapely polygon
strain_in Strain rate dataset as list of lists
[ [lat, lon, exx, eyy, exy], ...]
regime Dict of Shapely multipolygons for each deformation regime
Currently only Continental (C) and Ridge-transform (R)
implemented
{'C': Multipolygon, 'R': Multipolygon}
Output:
momentrate moment rate computed from strain rate summed
over area zone
"""
momentrate = 0.0
for (lat, lon, exx, eyy, exy) in strain_in:
# make Shapely point from lon, lat
point = shapely.geometry.Point((lon, lat))
# check if in area zone polygon
# TODO(fab): small area zones that do not include a strain rate
# grid node
if poly.intersects(point):
# get deformation regime
regime_key = strain.tectonicRegimeForPoint(point, regime)
# select values for cz and mc
if regime_key not in (strain.DEFORMATION_REGIME_KEY_C,
strain.DEFORMATION_REGIME_KEY_R):
# point not in available regimes, don't evaluate contribution
# from this point
continue
else:
(e1, e2, e3, e1h, e2h, err) = \
strain.strainRateComponentsFromDataset((exx, eyy, exy))
if regime_key == strain.DEFORMATION_REGIME_KEY_C:
# continental regime
if (
err <= strain.BIRD_CONTINENTAL_REGIME_COMPARISON_FACTOR * e2h \
and err >= strain.BIRD_CONTINENTAL_REGIME_COMPARISON_FACTOR * e1h):
# strike-slip faulting dominates
parameter_key = strain.DEFORMATION_REGIME_KEY_CTF
elif \
err > strain.BIRD_CONTINENTAL_REGIME_COMPARISON_FACTOR * e2h:
# thrust faulting dominates
parameter_key = strain.DEFORMATION_REGIME_KEY_CCB
else:
# normal faulting dominates
parameter_key = strain.DEFORMATION_REGIME_KEY_CRB
elif regime_key == strain.DEFORMATION_REGIME_KEY_R:
# ridge-transform regime
if e1h >= 0.0:
parameter_key = strain.DEFORMATION_REGIME_KEY_OSR
elif e2h < 0.0:
parameter_key = strain.DEFORMATION_REGIME_KEY_OCB
elif (e1h * e2h < 0.0 and (e1h + e2h) >= 0.0):
parameter_key = strain.DEFORMATION_REGIME_KEY_OTF
elif (e1h * e2h < 0.0 and (e1h + e2h) < 0.0):
parameter_key = strain.DEFORMATION_REGIME_KEY_OCB
else:
# never get here
raise RuntimeError, \
"Unexpected case in ridge-transform regime"
# TODO(fab): criterion for not adding contribution
cz = strain.BIRD_SEISMICITY_PARAMETERS[parameter_key]['cz']
if e2 < 0:
momentrate += (2 * cz * e3)
else:
momentrate += (2 * cz * -e1)
# convert original unit of [10^-9 yr^-1] to [s^-1]
return 1000 * SHEAR_MODULUS * 1.0e-9 * momentrate * (
60 * 60 * 24 * 365.25)
