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

Source:`R/model_shmax.R`

`superimposed_shmax_PB.Rd`

Calculates a \(\sigma_{Hmax}\) 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.

## Usage

```
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.

## Examples

```
na_grid <- sf::st_make_grid(san_andreas, what = "centers", cellsize = 1)
na_plate <- subset(plates, plateA == "na" | plateB == "na")
cpm <- subset(cpm_models, cpm_models$model == "NNR-MORVEL56")
# make divergent to ridge-push:
na_plate <- transform(na_plate, type = ifelse(na_plate$pair == "eu-na", "convergent", type))
res <- superimposed_shmax_PB(na_grid, na_plate, model = cpm, idp = 2)
head(res)
#> azi R
#> [1,] 36.78752 167.7019
#> [2,] 34.10380 178.7247
#> [3,] 31.98870 189.8442
#> [4,] 29.85757 201.7330
#> [5,] 28.37406 213.9229
#> [6,] 27.33043 226.3990
```