I'm actually not sure the Northridge earthquake was cited in the Richter scale, most references I see have it as about a 6.7, which based on the USGS catalog, was it's moment magnitude 6.7 Mw

https://earthquake.usgs.gov/earthquakes/eventpage/ci3144585/...

And today's earthquake for comparison:

https://earthquake.usgs.gov/earthquakes/eventpage/us6000qw60...

And some information of Magnitude types: https://www.usgs.gov/programs/earthquake-hazards/magnitude-t...

I think it's probably safe to assume, that today's earthquake is much more energetic at least.