inparam.model.yaml

inparam.model.yaml#

1D model#

Parameters for 1D model (the mesh).

exodus_mesh#

What: Exodus mesh file created by salvus mesher

Type: filename

Default: global_mesh__prem_ani__50s.e

geodesy#

Parameters for geodesy.

lat_lon_north_pole_mesh#

What: geographic location of the north pole in the mesh

Type: array of double / SOURCE

Default: SOURCE

Note:

  1. this reference location enables the usage of geographic coordinates for locating sources, receivers and 3D models, compatible with Cartesian meshes

  2. array of double: [latitude, longitude]

  3. SOURCE: determined this location by the FIRST source presented in list_of_sources in inparam.source.yaml; always use SOURCE for a single-source simulation

flattening_on_surface#

What: flattening on the surface

Type: string / double

Only: SPHERE / WGS84 / GRS80 / SPECFEM3D_GLOBE / value

Default: WGS84

Note:

  1. ellipticity is ignored for a Cartesian mesh

  2. 0 for a perfect sphere; ~0.0033 for the Earth

  3. ellipticity will be used in the transformation between the geographic and the geocentric co-latitudes; see eq. (14.32) in Dahlen & Tromp, 1998

  4. to actually deform the entire mesh, add 3D model “Ellipticity” to list_of_3D_models

absorbing boundary#

Parameters for absorbing boundary condition.

boundaries#

What: model boundaries regarded as absorbing boundaries

Type: array of string

Only: a subset of [RIGHT, BOTTOM, TOP]

Default: [RIGHT, BOTTOM]

Note:

  1. an AxiSEM3D mesh may contain four outer boundaries: left (axial), right, bottom and top (surface); the right, bottom and top ones can be absorbing boundaries (the left or axial one is non-physical)

  2. use [] to disable absorbing boundary condition (so that all model boundaries will be stress-free)

  3. the most common case in seismology is [RIGHT, BOTTOM]

enable_Clayton_Enquist#

What: enable the Clayton-Enquist approach

Type: bool

Default: true

Note:

the simplest linear approach by Clayton & Engquist (1977)

Kosloff_Kosloff#

the sponge approach by Kosloff & Kosloff (1986)

enable#

What: enable the Kosloff-Kosloff approach

Type: bool

Default: true

Note:

Clayton-Enquist and Kosloff-Kosloff can be used together, but one of them has to be enabled at least

relative_spans#

What: relative spans of the sponge layers

Type: array of double

Default: [.05, .05]

Note:

  1. must be presented in the same order as absorbing_boundaries

  2. to use Kosloff-Kosloff, the mesh should be a little larger than the required computational domain; for example, given a required domain spans from 0 to 100 km in depth, one can generate a mesh from 0 to 110 km and set the relative span to 0.05, so the thickness of the sponge layer at the mesh bottom will be determined as 110 * 0.05 = 5.5 km, leaving an unaffected depth range from 0 to 104.5 km for normal wave propagation and analysis

  3. allowed range: .01 ~ 0.25

gamma_expr_solid#

What: expression of γ-factor in solid domain

Type: math expression

Default: 1.1 / T0 * (VS / VP)^2 * exp(-0.04 * SPAN / (VP * T0))

Note:

  1. γ-factor represents the absorbing strength at a point

  2. allowed arguments include (case sensitive):

  • VP, VS: P- and S- wave velocities at the point

  • RHO : density at the point

  • SPAN : span of the sponge layer

  • T0 : mesh period

  • VP, VS and RHO are the 1D values in the Exodus mesh

  1. this expression will be further multiplied by a pattern function that equals to 1 on the outermost edge of the sponge layer (i.e., on the mesh boundary) and gradually decreases to 0 on the the innermost edge; such a decreasing pattern is automatically handled by the solver

  2. the default is an empirical expression from Haindl et al., 2020

gamma_expr_fluid#

What: expression of γ-factor in fluid domain

Type: math expression

Default: 0.88 / T0 * exp(-0.04 * SPAN / (VP * T0))

Note:

same as gamma_expr_solid but without VS dependency

attenuation#

attenuation#

What: attenuation mode

Type: string

Only: NONE / FULL / CG4

Default: CG4

Note:

  1. NONE: turn off attenuation

  2. FULL: compute attenuation on all GLL points

  3. CG4: compute attenuation on 4 GLL points per element; CG4 is mostly as accurate as FULL but more efficient than FULL, see van Driel & Nissen-​Meyer, 2014; CG4 requires NPOL_SEM set to 4 via CMake.

3D models#

list_of_3D_models#

What: list of 3D models

Type: array of objects

Default: []

Note:

  1. the order in this list can affect the final 3D model

  2. use [] if no 3D model presents