Gumbel · Fréchet · Weibull — Block Maxima & Return Levels
Extreme Value Theory (EVT) states that block maxima converge to the Generalized Extreme Value (GEV) distribution. Gumbel (ξ=0) for exponential tails, Fréchet (ξ>0) for heavy tails, Weibull (ξ<0) for bounded distributions. Return levels indicate thresholds exceeded on average once every T events.