def test_plane_obs():
modfile = resource_filename('telewavesim',
'examples/models/model_Audet2016.txt')
model = ut.read_model(modfile)
npts = 2000
wvtype = 'P'
dt = 0.05
slow = 0.04
baz = 0.
dp = 1000
c = 1.5
rhof = 1027
ut.model2for(model)
ut.wave2for(dt, slow, baz)
ut.obs2for(dp, c, rhof)
yx, yy, yz = pw_f.plane_obs(npts, model.nlay, np.array(wvtype, dtype='c'))
ux = np.real(fft(yx))
uy = np.real(fft(yy))
uz = np.real(fft(yz))
# seismogram should be maximized on vertical component
assert np.max(np.abs(uz)) > np.max(np.abs(ux)) > np.max(np.abs(uy)), \
'Failed! Energy is not maximized on vertical component'
# tangential component should all be close to zero
assert np.allclose(uy, np.zeros(len(uy))), 'non-zero values in uy'
def test_plane_obs(load_params):
yx, yy, yz = pw_f.plane_obs(cf.nt, cf.nlay, np.array(cf.wvtype, dtype='c'))
ux = np.real(pyfftw.interfaces.numpy_fft.fft(yx))
uy = np.real(pyfftw.interfaces.numpy_fft.fft(yy))
uz = np.real(pyfftw.interfaces.numpy_fft.fft(yz))
# seismogram should be maximized on vertical component
assert np.max(np.abs(uz)) > np.max(np.abs(ux)) > np.max(np.abs(uy)), \
'Failed! Energy is not maximized on vertical component'
# tangential component should all be close to zero
assert np.allclose(uy, np.zeros(len(uy))), 'non-zero values in uy'
def run_plane(obs=False):
"""
Function to run the ``plane`` module and return 3-component seismograms as an ``obspy``
``Stream`` object.
.. note::
The ``conf`` global variables need to be set for this calculation
to succeed. This function first checks to make sure the variables are all set
before executing the main ``telewavesim.rmat_f.plane_****`` function.
Args:
fortran (book, option): Whether or not the Fortran modules are used
obs (bool, optional): Whether or not the analysis is done for an OBS stations
Returns:
(obspy.stream): trxyz: Stream containing 3-component displacement seismograms
"""
# Check if all variables are set. If not, throw an Exception and stop
check_cf(obs)
# Pass variables to Fortran conf
model2for()
wave2for()
# Run the ``plane`` module depending on land or OBS case.
if obs:
# If OBS, then further pass OBS-related paramters to Fortran conf
obs2for()
# Get the Fourier transform of seismograms for ``obs``case
yx, yy, yz = pw_f.plane_obs(cf.nt,cf.nlay,np.array(cf.wvtype, dtype='c'))
else:
# Get the Fourier transform of seismograms for ``land`` case
yx, yy, yz = pw_f.plane_land(cf.nt,cf.nlay,np.array(cf.wvtype, dtype='c'))
# Transfer displacement seismograms to an ``obspy`` ``Stream`` object.
trxyz = get_trxyz(yx, yy, yz)
return trxyz
def run_plane(model,
slow,
npts,
dt,
baz=0,
wvtype='P',
obs=False,
dp=100.,
c=1.5,
rhof=1027):
"""
Function to run the ``plane`` module and return 3-component seismograms as
an ``obspy.Stream`` object. This function builds the seismic response
spectrum by frequency using the matrix propagation approach.
Required arguments are the seismic model, slowness value, and the sampling
properties (maximum number of samples and
the sampling distance in seconds).
By default, the function uses a back-azimuth value of 0 degree,
which is suitable for events coming from the North pole or isotropic
seismic velocity models (i.e., those that do not vary with direction of
incoming waves).
For anisotropic velocity models, users need to specify the back-azimuth
value in degrees. Furthermore, the default type of the incoming
teleseismic body wave is ``'P'`` for compressional wave. Other options are
``'SV'``, ``'SH'``, or ``'Si'`` for vertically-polarized shear wave,
horizontally-polarized shear wave or isotropic shear wave, respectively.
Wave modes cannot be mixed.
Finally, it is possible to simulate the seismic response for ocean-bottom
seismic (OBS) stations using the flag ``obs=True``. If the flag is set to
``True``, the user can specify the water depth below sea level
(in meters, positive value) as well as the properties of the sea water
(defaults are acoustic wavespeed of 1.5 km/s and density of 1027 kg/m^3).
Args:
model (Model):
Instance of the ``Model`` class that contains the physical
properties of subsurface layers.
slow (float): Slowness (s/km)
baz (float): Back-azimuth (degree)
npts (int): Number of samples in time series
dt (float): Sampling distance (s)
baz (float, optional): Back-azimuth (degree)
wvtype (str, optional, default: ``'P'``):
Incident wavetype (``'P'``, ``'SV'``, ``'SH'``, ``'Si'``)
obs (bool, optional):
Whether or not the analysis is done for an OBS stations
dp (float, optional): Deployment depth below sea level (m)
c (float, optional):
P-wave velocity of salt water (default = ``1.5`` km/s)
rhof (float, optional):
Density of salt water (default = ``1027.0`` kg/m^3)
Returns:
(obspy.stream):
trxyz: Stream containing 3-component displacement seismograms
Example
-------
Basic example:
>>> from telewavesim import utils
>>> # Define three-layer model with isotropic crust and antigorite upper mantle layer over isotropic half-space
>>> model = utils.Model([20, 10, 0], [2800., None, 3300.], [4.6, 0, 6.0], [2.6, 0, 3.6], ['iso', 'atg', 'iso'], [0, 0, 0], [0, 0, 0], [0, 0, 0])
>>> slow = 0.06 # s/km
>>> npts = 1500
>>> dt = 0.025 # s
>>> st = utils.run_plane(model, slow, npts, dt)
>>> type(st)
<class 'obspy.core.stream.Stream'>
>>> print(st)
3 Trace(s) in Stream:
...N | 1970-01-01T00:00:00.000000Z - 1970-01-01T00:00:37.475000Z | 40.0 Hz, 1500 samples
...E | 1970-01-01T00:00:00.000000Z - 1970-01-01T00:00:37.475000Z | 40.0 Hz, 1500 samples
...Z | 1970-01-01T00:00:00.000000Z - 1970-01-01T00:00:37.475000Z | 40.0 Hz, 1500 samples
>>> st.plot(size=(600, 450))
.. figure:: ../telewavesim/examples/picture/Figure_land.png
:align: center
OBS station:
>>> from telewavesim import utils
>>> # Define two-layer model with foliated eclogitic crust over isotropic half-space
>>> model = utils.Model([20, 0], [None, 3300.], [0, 6.0], [0, 3.6], ['EC_f', 'iso'], [0, 0], [0, 0], [0, 0])
>>> slow = 0.06 # s/km
>>> npts = 3000
>>> dt = 0.01 # s
>>> wvtype = 'SV'
>>> baz = 45.
>>> dp = 1000.
>>> st = utils.run_plane(model, slow, npts, dt, baz=baz, wvtype=wvtype, obs=True, dp=dp)
>>> st.plot(size=(600, 450))
.. figure:: ../telewavesim/examples/picture/Figure_obs.png
:align: center
"""
# Pass variables to Fortran conf
model2for(model)
wave2for(dt, slow, baz)
# Run the ``plane`` module depending on land or OBS case.
if obs:
# If OBS, then further pass OBS-related paramters to Fortran conf
obs2for(dp, c, rhof)
# Get the Fourier transform of seismograms for ``obs``case
yx, yy, yz = pw_f.plane_obs(npts, model.nlay,
np.array(wvtype, dtype='c'))
else:
# Get the Fourier transform of seismograms for ``land`` case
yx, yy, yz = pw_f.plane_land(npts, model.nlay,
np.array(wvtype, dtype='c'))
# Transfer displacement seismograms to an ``obspy`` ``Stream`` object.
trxyz = get_trxyz(yx, yy, yz, npts, dt, slow, baz, wvtype)
return trxyz