Sources and Receivers

The src_rec/ directory in the project contains input files for defining sources and receivers FWAT.

Source list

The source list is used to define the sources for the FWAT. The source file name should be sources_${dat_type}.dat, where ${dat_type} is the simulation type, such as noise for ambient noise tomography, tele for teleseismic tomography or rf for receiver function adjoint tomography. The source list file contains the following columns:

event_name: The name of the event, which is used to define the source and receiver file name.
event_lat: The latitude or Y coordinate of the event in degrees.
event_lon: The longitude or X coordinate of the event in degrees.
event_depth: The depth of the event.
event_buried: The buried depth of the event.
event_weight: The weight of the event, which is applied to objective function and adjoint source.

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For teleseismic tomography, the event_lat, event_lon, event_depth and event_buried are not used due to the definition of back-azimuth and take-off angle of the injected plane wave, but they are required for the source list file format.

Source files

Different simulation types require different source files in the src_rec/ directory. Below are the source files for different simulation types:

Ambient Noise Tomography

For ambient noise adjoint tomography, the force solution is used as the source. the source file name should be FORCESOLTION_${event_name} and the format is the same as that in Specfem3D.


FORCE  001
time shift:     0.0000
f0:             0.5
latorUTM:       -0.8209138629358446
longorUTM:      -0.820465815889425
depth:          0.0000
source time function:            0
factor force source:             1.d15
component dir vect source E:     0.d0
component dir vect source N:     0.d0
component dir vect source Z_UP:  1.d0

Teleseismic Tomography

The plane wave will be injected into SEM domain for teleseismic simulation, including teleseismic and receiver function adjoint tomography. Frequency-wavenumber (FK) will be used to calculate the injection plane wave. The FKmodel_${event_name} file is used to define the FK model for the teleseismic source.


# 
#  input file for embedded FK modeiling 
#
#  for each layer we give : 
#  LAYER ilayer rho vp vs ztop
#  the last layer is the homogeneous half space 
#
#
# model description  ---------------------
NLAYER             2
LAYER 1 2625. 6375. 3750. 0
LAYER 2 3136. 7616. 4480. -40000.
#----------------------------------------
# incident wave p or sv 
INCIDENT_WAVE      p
#----------------------------------------
# anlges of incomming wave
BACK_AZIMUTH           0
TAKE_OFF               27.191115158518674
#----------------------------------------
FREQUENCY_MAX      0.55
#----------------------------------------
TIME_WINDOW      200.
#----------------------------------------
# optional 
# ORIGIN_WAVEFRONT  299673.1 22116.76 -150000.
# ORIGIN_TIME 0.

Receiver files

The receiver files are used to define the receivers locations for the FWAT. The receiver file name should be STATIONS_${event_name} and the format is the same as that in Specfem3D. The file contains 6 columns: station station, network, latitude, longitude, elevation, and buried depth. Below is an example of the receiver file:


ST000 MX -0.20 0.40 0.00 0.00
ST001 MX -0.20 0.50 0.00 0.00