Map view of the B_β(x₁, x₂) in the vicinity of the fault for different values of the weakening parameter. From left to right and top to bottom: β = 1.2, 1.5, 3, 5. Note the same shape of the function in the four different cases. The black line emphasizes the limit of the domain of confidence over which the function is nearly constant and equals β. The size of this domain is an increasing function of β.