fmi_parameters {eseis}

Create reference model reference parameter catalogue

Description

In order to run the fluvial model inversion (FMI) routine, a set of randomised target parameter combinations needs to be created. This function does this job.

Usage

fmi_parameters(
  n,
  d_s,
  s_s,
  r_s,
  q_s,
  h_w,
  w_w,
  a_w,
  f_min,
  f_max,
  r_0,
  f_0,
  q_0,
  v_0,
  p_0,
  e_0,
  n_0_a,
  n_0_b,
  res
)

Arguments

n

Numeric value, number of output reference spectra.

d_s

Numeric value, mean sediment grain diameter (m). Alternative to gsd.

s_s

Numeric value, standard deviation of sediment grain diameter (m). Alternative to gsd.

r_s

Numeric value, specific sediment density (kg / m^3)

q_s

Numeric value, unit sediment flux (m^2 / s)

h_w

Numeric value, fluid flow depth (m)

w_w

Numeric value, fluid flow width (m)

a_w

Numeric value, fluid flow inclination angle (radians)

f_min

Numeric value, lower boundary of the frequency range to be modelled.

f_max

Numeric value, upper boundary of the frequency range to be modelled.

r_0

Numeric value, distance of seismic station to source

f_0

Numeric value, reference frequency (Hz)

q_0

Numeric value, ground quality factor at f_0. "Reasonable value may be 20" (Tsai et al. 2012).

v_0

Numeric value, phase speed of the Rayleigh wave at f_0 (m/s). Assuming a shear wave velocity of about 2200 m/s, Tsai et al. (2012) yield a value of 1295 m/s for this parameter.

p_0

Numeric value, variation exponent of Rayleigh wave velocities with frequency (dimensionless)

e_0

Numeric value, exponent characterizing quality factor increase with frequency (dimensionless). "Reasonable value may be 0" (Tsai et al. 2012).

n_0_a

Numeric value, lower Greens function displacement amplitude coefficients. Cf. N_ij in eq. 36 in Gimbert et al. (2014)

n_0_b

Numeric value, lower Greens function displacement amplitude coefficients. Cf. N_ij in eq. 36 in Gimbert et al. (2014)

res

Numeric value, output resolution, i.e. length of the spectrum vector.

Details

All parameters must be provided as single values, except for those parameters that shall be randomised, which must be provided as a vector of length two. This vector defines the range within which uniformly distributed random values will be generated and assigned.

Value

List object with model reference parameters.

Author(s)

Michael Dietze

Examples

## create two parameter sets where h_w (water level) and q_s (sediment
## flux) are randomly varied.

ref_pars <- fmi_parameters(n = 2,
                           h_w = c(0.02, 2.00),
                           q_s = c(0.001, 50.000) / 2650,
                           d_s = 0.01,
                           s_s = 1.35,
                           r_s = 2650,
                           w_w = 6,
                           a_w = 0.0075,
                           f_min = 5,
                           f_max = 80,
                           r_0 = 6,
                           f_0 = 1,
                           q_0 = 10,
                           v_0 = 350,
                           p_0 = 0.55,
                           e_0 = 0.09,
                           n_0_a = 0.6,
                           n_0_b = 0.8,
                           res = 100)