As an action, a wave of thunderous force sweeps out from you in a thunderous boom audible out to 100 meters. Unsecured objects that weigh up to 100 kilos and are completely within the area of effect are automatically pushed 2 meters away from you. Each creature other than you in a sphere centered on you must make a Fortitude saving throw.
On a failure, it takes 5d4 concussion damage, is deafened for 1 minute, and is pushed 2 meters away from you if it is Medium or smaller.
On a critical failure, it takes twice as much damage and is pushed 4 meters away from you if it is Medium or smaller.
On a success, it takes half as much damage.
On a critical success, it takes no damage.
A deafened creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.
Augment
You can increase the damage by 3d4, push each creature an additional meter, affect a creature of a larger size, and the maximum weight of objects that you can affect with this spell increases by 150 kilos for each additional mana expended.
Thunderwaves. You can expend 1 additional mana so the thunderous force continuously sweeps out from you. The duration changes to 1 minute/mana, concentration and the thunderous force sweeps out from you in an aura shaped as a sphere. Until the spell ends, the aura moves with you, centered on you.
Whenever a creature enters the area for the first time on a turn or starts its turn there, it must make the Fortitude saving throw. The damage is reduced to 3d4 and additional augments to the damage increase the damage by 1d4 for each additional mana expended, instead of the normal increase.