Rocky Mountain fireball On 10 August 1972, Earth’s atmosphere was grazed by a large meteor travelling from south to north over western United States. The spectacular daytime fireball was filmed over Grand Teton National Park, Wyoming. It eventually exited the atmosphere north of Edmonton, Alberta. Satellite data suggest the meteor had a diameter of 15 to 80 metres and a mass of at least several thousand tonnes. At its closest approach it was about 58 kilometres above Montana. Had it hit the Earth, it would have produced an explosion equal to between one and twenty kilotonnes of TNT. 11:36 AM
22.9.06
Tsunamis at sea The safest place to experience a tsunami is at sea. Although tsunami waves can travel at more than 700 kilometres per hour, over deep oceans tsunami waves are very broad and low, so ships can ride over them safely 3:31 PM
15.9.06
Sonic boom over Canterbury On Tuesday, 12 September 2006, just before 3 pm, a loud sonic boom rattled homes in the Canterbury region. The noise was heard from Wellington to Invercargill, and ground shaking was by recorded by GNS seismographs at McQueen’s Valley and Cashmere Hill. Many people reported a glowing object streaking across the sky and breaking into several fragments. It is still uncertain if the object was a meteor or man-made space debris. A glazed black lump of material was found in a field at Dunsandel, but scientists say it is not a meteorite. 2:20 PM
8.9.06
Glacier slide on Ruapehu On Wednesday, 30 August 2006, at 5.30 am, about 25,000 cubic metres of ice and snow broke off an ice cliff under Paretetaitonga peak and collapsed into Mount Ruapehu’s crater lake. Parts of the lake shot three metres into the air and mini-icebergs were left floating on the lake. 2:56 PM
1.9.06
Noisy volcano In 1883 the volcano Krakatoa, which lies in the Sunda Straits between Java and Sumatra, exploded in a series of massive eruptions. The sound of three great eruptions on 27 August was heard over a huge area. The noise was loud enough to blow out windows at Batavia, 160 kilometres away. The sound woke sleeping people at Elsey Creek in South Australia, 3,224 kilometres from Krakatoa. The furthest point where the eruptions were heard was Rodriguez Island, in the Indian Ocean, 4,811 kilometres away. 12:25 PM
