For every 10 stacks of tremor, Target's AC is lowered by one. Upon inflicting Tremor Burst, the target with Tremor must make a Constitution saving throw with DC being equal to the Tremor stack. On fail, the target is Stunned. After Tremor Burst, Tremor on a target is halved. A creature may only have a maximum of 99 Tremor. Tremor is removed after 2 consecutive rounds of not being hit.
Tremor Burst is stated on skills.
tremor can be burst many times in one action if so it is halved until either you no longer are bursting tremor or the tremor falls below 10