There are cases where it is preferred to send your logs in JSON format.
Because JSON format is easier to parse.
So if you want to send your logs to a SIEM like the ELK or  IBM QRadar you have to make
the following changes at the Zeek Configuration.

Add to /opt/zeek/share/zeek/site/local.zeek

 @load policy/tuning/json-logs.zeek