Breaking of the Seal

Seal on Kalshazzak's tomb ensured in part by a weapon driven through his body, pinning him in place.
Over time, temple was built around this weapon and his mortal remains, came to be seen as a holy relic.
Before earthquake, thieves broke in and stole the relic, wrenching it free from the altar-sarcophagus containing Kalshazzak's remains
Shortly after their escape, earthquake happened and the entire temple was drawn deep beneath the surface, covering up the theft and protecting Kalshazzak's partially bound form as he works to rid himself of the seal entirely.