superimposed_shmax_PB function

SHmax direction resulting from multiple plate boundaries considering distance to plate boundaries

Calculates a $SHmax$ direction at given coordinates, sourced by multiple plate boundaries. This first-order approximation is the circular mean of the superimposed theoretical directions, weighted by the rotation rates of the underlying PoRs, the inverse distance to the plate boundaries, and the type of plate boundary.

superimposed_shmax_PB(
  x,
  pbs,
  model,
  rotation_weighting = TRUE,
  type_weights = c(divergent = 1, convergent = 3, transform_L = 2, transform_R = 2),
  idp = 1
)

Arguments

• x: grid. An object of sf, sfc or 2-column matrix
• pbs: plate boundaries. sf object
• model: data.frame containing the Euler pole parameters. See equivalent_rotation() for details.
• rotation_weighting: logical.
• type_weights: named vector.
• idp: numeric. Weighting power of inverse distance. The higher the number, the less impact far-distant boundaries have. When set to 0, no weighting is applied.

Returns

two-column matrix. azi is the resultant azimuth (in degrees), R

is the resultant length.

Examples

na_grid <- sf::st_make_grid(san_andreas, what = "centers", cellsize = 1)
na_plate <- subset(plates, plateA == "na" | plateB == "na")
cpm <- cpm_models[["NNR-MORVEL56"]]

# make divergent to ridge-push:
na_plate <- transform(na_plate, type = ifelse(na_plate$pair == "eu-na", "convergent", type))

res <- superimposed_shmax_PB(na_grid, na_plate, model = cpm, idp = 2)
head(res)

See Also

superimposed_shmax()