Who truncated the table and what time

 SET NOCOUNT ON;

  DECLARE @ObjectName SYSNAME

  DECLARE @TransactionID NVARCHAR(500)

  SET @ObjectName = 'dbo.tablename'

 

  SELECT @ObjectName AS ObjectName

      ,   [Transaction Name]

      ,   SUSER_SNAME([Transaction SID]) AS UserName

      ,   [Begin Time]

      ,   Operation

      ,   [Transaction ID]

      FROM fn_dblog(NULL, NULL)

        where   [Transaction Name] LIKE 'TRUNCATE%'

          AND Operation = 'LOP_BEGIN_XACT'