It is the strain energy acumulated due to acting stress.This energy can be released suddenly as a kinetic energy or dissipated slowly during the irreversible deformation.

Thank you Zuberek. how can i cause rockburst by accumulation of energy in rock?

The energy does not accumulate in the rock that explodes, but, it is energy radiated from the point of rupture of the rock mass. That is to say, the tensile strength of the exploding rock is the one that is surpassed by the tensile wave, which is a product of the reflection of the compression wave.

When I worked in a deep mine the rock bursts were caused by just making the tunnel at that depth. The burst pushed one side of the wall out into the drift (opening). The rock stretched, so to speak.

Thank you dear Marcelo and Michael.

I want to simulate energy of rock burst in Flac 3D But how I dont know. I mean I want to cause rock burst by increasing energy in Flac 3D.

I appreciate that if you help me.