Coordinates: -53.0412 S 72.5968 E
No:183        (list of all attractions)
Category:Volcanoes
Values:Geology, Visual
Rank:7
Address:Antarctic and Sub-antarctic region, Australia, Heard Island and McDonald Islands, McDonald Island
Alternate names:McDonald Islands
Height:230 m?
Last eruption:2005?

Unusual changes transformed McDonald Islands in the time period from 2000 to 2001. Volcanic eruptions and (possibly) rise of the land increased the area of main McDonald Island from 1.13 km² to 2.45 km², rising the height of tallest mountain from 186 to 230 m.

Late discovery

McDonald Islands are very remote and little known islands. They were first sighted exactly 157 years ago - in 4th January 1854 - from ship "Samarang" and were named after the captain William McDonald. Highest (then) hill on island was named after ship - Samarang Hill. This is comparatively late discovery of new lands outside polar regions.

Back then this was a group of three small islands - 186 m high McDonald Island itself, 55 m high Flat Island a little north from it and Meyer Rock - impressive cliff rising from the sea 1.9 km to the north-west from McDonald Island. By the way - Meyer Rock is barely visible on Google Earth.

Although island represented a summit of volcano, it seemed to be a relatively peaceful place with many thousands of macaroni penguins (Eudyptes chrysolophus) breeding on it (see image).

People have not lived here and up to this day the island has been visited few times. One of the main reasons for rare visits is nearly impossible landing due to permanently rough sea.

Sudden eruptions

Volcano of McDonald Island was dormant for 75,000 years but in 1992 it suddenly became active. Several eruptions have taken place since then with volcanic plumes observed in December 1996 and January 1997, when floating pumice reached also Heard Island.

Especially significant changes took place in 2000 - 2001. Satellite image from November 2000 shows no major changes to the island geography. Image from 2001 though shows completely different picture. Island has extended, mainly towards the north, joining with Flat Island. The highest point of island has shifted to the north.

Last known eruption took place in 2005.

Island is built of layered phonolitic tuff and cut by phonolitic dikes - thus the geology here is completely different from the geology of 45 km distant Heard Island. During the eruption volcano exuded highly viscous, slowly flowing lava.

Google Earth image shows muddy water around the island - active erosion process is ongoing and newly extended island again is washed out. Western side of the island is exposed to rough winds and constant giant waves - it represents giant, more than 200 m tall vertical cliff.

Return of life

During the eruptions there was destroyed almost all vegetation of island. Nevertheless satellite images show green patches of plants - they are quickly colonising the new land.

Most likely eruptions disturbed also macaroni penguins. But the pumice fields may represent a good breeding site for them and it is possible that also king penguins (Aptenodytes patagonicus) will choose to breed here - or may be they already are here.

Map

See McDonald Islands on the map of Heard Island and McDonald Islands!

References

  1. McDonald Island, image from the times when there were three separate islands, accessed 03.01.11.
  2. McDonald Island, rare image taken on the island in 1980, accessed 03.01.11.
  3. McDonald Island, shape of the island in 1980, accessed 03.01.11.

Creative Commons Non-Commercial Share Alike 3.0 4 January 2011 Gatis Pāvils

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