A very common leak point on the Miata is the Cam Angle Sensor O-ring.
It's not too hard to replace, so it should be done if your engine is leaking a lot of oi.
This is likely the source of a big oil leak.

One O-ring will service all 1.6L engines 90-93 and also all 1.8L engines 94-97.

Get an extra to throw in the glove box. Then it's easy to find a new O-ring when it leaks the next time. (There is always a next time if you keep the car for a while, lol)

Images show the O-ring by itself and also installed on a CAS as an example.
O ring only in this product listing.