(ROUGH CUT ONLY - NO REPORTER NARRATION)<br/> <br />Aerial videos show thick grey ashes blanketing part of New Zealand's central North Island.<br/> <br />Mount Tongariro roared to life after being dormant for 115 years, spewing boulders and spreading ash cloud on Monday night (August 6).<br/> <br />Flights to and from provincial destinations, including renowned tourist spot Rotorua, were delayed or cancelled and local highways were closed for a time, but no other damage or injuries were reported.<br/> <br />Craters on Mount Tongariro, one of the three volcanic peaks in the central North Island, exploded with bright flashes and thunderous booms.<br/> <br />Volcanologists said the scale of the eruption was unexpected.<br/> <br />And the spew of rocks was caused by pressure build-up of volcanic gases, since seismic activity had increased in recent weeks.<br/> <br />The last time Mount Tongariro erupted was in 1897, ending a decades-long period of intermittent activity.
