premise: A surfer is surfing catches a wave.
hypothesis: A surfer is riding a tsunami wave.
explanation_1: You can not infer it's a tsunami.
explanation_2: Not all waves are tsunami waves.
explanation_3: The wave is just a wave according to sentence one. A tsunami sized wave is not implied.
premise_logic: exists x1.(all x2.(n_wave(x2) -> exists e1 x3.(Theme(e1,x3) & Actor(e1,x1) & v_surf(e1) & for(x3,x2) & n_catch(x3))) & n_surfer(x1))
hypothesis_logic: exists e1 x1 x2 x3.(Theme(e1,x2) & Actor(e1,x1) & v_ride(e1) & n_wave(x2) & of(x2,x3) & n_tsunami(x3) & n_surfer(x1))