diff --git a/src/coreComponents/physicsSolvers/wavePropagation/sem/acoustic/secondOrderEqn/anisotropic/AcousticVTIFletcherWaveEquationSEM.cpp b/src/coreComponents/physicsSolvers/wavePropagation/sem/acoustic/secondOrderEqn/anisotropic/AcousticVTIFletcherWaveEquationSEM.cpp
index 13dc9ba770..3d6427da74 100644
--- a/src/coreComponents/physicsSolvers/wavePropagation/sem/acoustic/secondOrderEqn/anisotropic/AcousticVTIFletcherWaveEquationSEM.cpp
+++ b/src/coreComponents/physicsSolvers/wavePropagation/sem/acoustic/secondOrderEqn/anisotropic/AcousticVTIFletcherWaveEquationSEM.cpp
@@ -114,6 +114,7 @@ void AcousticVTIFletcherWaveEquationSEM::registerDataOnMesh( Group & meshBodies
 
       subRegion.registerField< acousticvtifields::AcousticDelta >( getName() );
       subRegion.registerField< acousticvtifields::AcousticEpsilon >( getName() );
+      subRegion.registerField< acousticvtifields::AcousticSigma >( getName() );
     } );
 
   } );