Lerr is obtained through tracing the variety of elastic energy density of each element and recording the maximal fluctuation when brittle failure happens during numerical calculation 该指标的实现是通过在数值计算中追踪每个单元弹性能量密度变化的全过程，记录单元发生脆性破坏前后的弹性能密度差值，得到单位体积岩体突然释放的弹性能量。
