[docs]
def unit_normal( strike , dip ):
"""Return unit vector normal to the fault plane in ENU (Up positive upward).
Parameters
----------
strike : float
Fault strike in degrees.
dip : float
Fault dip in degrees.
Returns
-------
tuple of float
(unit_E, unit_N, unit_U) in ENU.
"""
import numpy as np
rstrike = np.radians( strike )
rdip = np.radians( dip )
unit_E = np.sin( rdip ) * np.cos( rstrike )
unit_N = -np.sin( rdip ) * np.sin( rstrike )
unit_U = np.cos( rdip )
return( unit_E , unit_N , unit_U )