Did someone else notice the hash spike just a few minutes ago?
it was around 1,1 TH/s and then dropped to 40-30 GH/s.
Nethash is not measured, it is estimated.
If you have block 10 with difficulty 50, then when block 11 is mined, you can estimate the nethash based on the difficulty and the time between the two blocks. Now, the difficulty is adjusted each block to try to make sure that blocks are spaced 30 seconds apart, based on the estimated nethash..
So what happens when a block is found, say, 5 seconds after the last block? The estimated nethash goes up, because it seems to the wallet that there has been a massive spike in hashpower.
So, most likely, the nethash did not go to 1.1TH/s, two blocks were just found increadibly close to each other.