The eruption cloud disrupted air travel, occasionally closing airports and the central North Island airspace.
2.
Particles falling from the eruption clouds form layers on the ground ( this is pyroclastic fall or tephra ).
3.
The eruption lasted for 24 hours and included " two initial explosive pulses and pauses over a 6-hr period that produced ash-poor eruption clouds, a 10-hr period of continuous ash-rich emissions initiated by an explosive pulse and punctuated by two others, and a final 8-hr period of waning ash emissions ."