cartography - How to style points in QGIS based on multiple attributes

While trying to find a useful way having earthquakes displayed, I noticed that it isn't that easy to manage.

I'd like to be able to recognize the "Magnitude", "Date", and "Depth" from the style of the point. Something like:

• size: based on magnitude


• depth: basic color (ex. <15 red, 15-30 yellow, >30 blue)


• date: intensity of color as shading from 100% color to white/...

Is there a way to do so without defining dozens of rules?