diff --git a/dune/tectonic/nicefunction.hh b/dune/tectonic/nicefunction.hh
index 6a30e3386f6d4ff513e6e157f89b1df37d826cfc..07f6e606f70fba3c89a12b54559bd56169c8abf8 100644
--- a/dune/tectonic/nicefunction.hh
+++ b/dune/tectonic/nicefunction.hh
@@ -37,20 +37,19 @@ class RuinaFunction : public NiceFunction {
   RuinaFunction(double coefficient, double a, double mu, double eta,
                 double normalStress, double b, double state, double L, double h)
       : a(a),
-        mu(mu),
         eta(eta),
         h(h),
         coefficientProduct(coefficient * normalStress),
-        K(b *
-          (state - std::log(eta * L))), // state is assumed to be logarithmic
-        rho(std::exp(-(mu + K) / a)) {}
+        K(mu + b * (state - std::log(eta * L))), // state is assumed to be
+                                                 // logarithmic
+        rho(std::exp(-K / a)) {}
 
   double virtual leftDifferential(double x) const {
     double const arg = x / h * eta;
     if (arg <= rho)
       return 0;
 
-    double const ret = a * std::log(arg) + mu + K;
+    double const ret = a * std::log(arg) + K;
     return coefficientProduct * ret;
   }
 
@@ -77,7 +76,6 @@ class RuinaFunction : public NiceFunction {
 
 private:
   double const a;
-  double const mu;
   double const eta;
   double const h;
   double const coefficientProduct;