Hi Petra - I also use a similar distance calculator - noted below. It is as the crow flies.

When I mentioned radius - I wasn't referring to your tones and how you figure out the location of a quake, I was referring to the Range/Radius field in the prediction form. When you are near some of the heavier earthquaked areas, a tighter focus should be used, maybe, to account for erroneous hits, like 20km instead of 40km.

Canie

• Distance calculator