McDonald Islands (volcano)
| McDonald Islands | |
|---|---|
| Highest point | |
| Elevation | 230 m (750 ft) |
| Geography | |
| Location | Heard Island and McDonald Islands, Australia |
| Geology | |
| Mountain type | Complex volcano |
| Last eruption | July 2005 |
The McDonald Islands is a volcano in the Indian Ocean. The islands currently belong to Australia. The islands had never erupted in recorded history prior to 1992.
Morphology
The McDonald Islands Volcano is made up of three islands: Mcdonald island, Flat island (which later merged with McDonald island) and Meyer Rock. The islands are mostly composed of Phonolitic pumice, dikes and lava domes The islands sit atop a Submarine plateau, the Kerguelen plateau. The islands are located around 75 km away from Heard Island.
McDonald island is the largest of the islands, at around 1 km2 in area. It has been the main focus of activity in recent times. Prior to 1996, McDonald island had been a flat green island whose pumice beaches provided a great nesting area for Penguin breeding. The island now has two main peaks, Maxwell Hill and Samarang Hill, the highest is Maxwell Hill at 230 M.
Eruptions
Prior to 1992, no eruptions had taken place at the Mcdonald Islands Volcano for 75,000 years. A series of eruptions started in 1992, with the last eruption occurring in 2004 (suggested by satellite imagery).
1992 eruption
The first historical eruption from the McDonalds was from a nearby submarine vent (a small VEI 0 Eruption) sometime in December 1992. The eruption was probably the cause of pumice that washed up on the shore of Heard Island.
1996-1997 eruption
Fresh eruptions were reported in December 1996 when a vapour plume was noticed by an aeroplane pilot. The plume was thought to have originated with Heard Island's Big Ben cone. However, on 18 March 1997 a passing ship headed for Heard Island reported that steam rose vigorously from a fissure on McDonald Island's steep north face, steam also vented from the island's north summit. Steam vented from a rubble-covered slope, indicating a lava flow or pyroclastic flow had occurred. On April 2, another ship noted that steam continued to vent from the fissure, with steam fising from the summit and flanks of the island. They also observed lava flows travelling down gullies, the lava flows covered a significant part of the North part of the island. Sulphur deposits were also discovered. Fresh pumice washed up on nearby Heard Island. The eruption ended sometime in January–March 1997.
2001 eruption
An eruption started again at McDonald Island some time in 2001. The eruption was first sighted from a ship passing by the islands. Material was being ejected from the flanks of the island and also in the north and northwest of the island, and steam was issuing from near the summit crater. Work suggested that prior to the ships visit, the volcano had been erupting, covering the island in dark, smooth material. Many features had been filled in, such as Williams Bay. The eruptions had also joined Flat Island to McDonald Island. 400 m of land had been added to windward point. A new volcanic cone had also been created. An observation made in November 2002 noted two new lava domes had been formed; when they formed is unknown.
2005 eruption
Analysis of satellite imagery noted that an eruption took place on July 12, 2005 on the northwest shore of the island. The eruption may have added a small portion to the area of the island.
Heritage
In 2002 the Heard and McDonald islands were declared as Marine reserve. The Islands are also recognized as a World Heritage Site.
References
External links
Coordinates: 53°3′34.9″S 72°35′32.2″E / 53.059694°S 72.592278°E