Hashrate distribution can indeed only be inferred from the rate of block production and their difficulties. And you need quite a few samples to get a clear pict

Hashrate distribution can indeed only be inferred from the rate of block production and their difficulties. And you need quite a few samples to get a clear picture (Poisson distribution). EDIT: It would probably be faster to determine the speed of the Cash fork by noticing the reduction in hash rate on the main Bitcoin network.