Something's throwing high severity errors and SQL is writing out stack dumps to log information which may help identify and fix the problem (severity 22 are severe errors which need to be addressed as a matter of urgency). Either investigate the cause of the errors yourself or open a case with Microsoft support and get their help. The main concern here is not the large log directory, it's those severity 22 errors (the highest possible severity is 25)
Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability