The tunnel size does not impact an earthquake, or at least not as a first order effect.
The collapse of a tunnel could create a sinkhole, but for most cases your tunnel very close to the surface and/or have a very large tunnel. Unless this was a large event you probably wouldn’t notice it if you didn’t see or hear it occur.
Now what does create earthquake in relationship to tunnels is pressure release. This usually occurs during the tunneling process, but outside forces can do the job just as well.
Typically this occurs where gas (typically natural gas) or liquids (typically water unless the tunnel was prospecting for something like oil) under pressure burst into the tunnel. the change in pressure can affect a sizable area like a large hydraulic ram relaxing beneath a whole area. Granted that is unlikely to affect a very large area, but it has occurred.
Another version would be frakking or similar technologies. Drill a hole and apply hydraulic pressure until something underground blows out. Here you adding pressure to a system with a sudden release. Again wide area effects are uncommon, but if you’re doing this all the time, across a large area, you will get periodic wide effects.
