Travelling Australia
Tower Hill
Crater wall
Internal wall of the Tower Hill crater showing layers of ash and scoria.
Detail of crater internal wall
Layers of ash and scoria form a tuff wall characteristic of maar craters.
Tower Hill is an inactive volcano beside the Warrnambool to Port Fairy Road. Tower Hill contains a 'maar' crater formed at least 30,000 years ago when hot magma came into contact with ground water resulting in violent explosions and a distinctive, flat-bottomed crater.

The first event at Tower Hill was a massive explosion when a lava column rising through the crust towards the surface came into contact with ground water; the water turned to steam, expanded violently and blew out the ground above hurling rocks, scoria and ash into the air.

Subsequent explosions ejected more ash and scoria; some blew over the surrounding country, but much of the material settled in layers around the crater rim forming a landform known as a tuff ring. The wide crater formed this way is known as a "maar" crater defined as a broad, shallow, flat-floored crater caused by hot magma coming in contact with ground water.

A maar usually fills with water forming a shallow crater lake. At Tower Hill subsequent activity, less violent than the first phase, generated several small cones of scoria and coarse volcanic fragments which are now surrounded by a shallow crater lake.

During the nineteenth century Tower Hill was treated as nothing special; much of the original vegetation was cleared and the slopes used for grazing, cropping or growing vegetables. In 1892 Tower Hill was declared as Victoria's first National Park but regulations were not enforced; grazing, cropping, timber cutting and burning, quarrying and rubbish dumping continued and by 1950 the islands within the crater and the crater walls were bare, pests were common, and little wildlife remained.

Tower Hill was declared a State Game Reserve in 1961 in the hope that the original condition of the crater and slopes could be restored. By then the slopes had been so seriously denuded for so long that nothing of the original vegetation remained so restoration relied on a painting by Eugene von Guerard done in 1855 and so detailed that plant species could be recognised. Identity of other species could be inferred from the habitat. Replanting of selected species continued until nearly 250,000 had been planted by 1981. Removal of introduced non-native plants and weeds has been an ongoing project. Restoration of tree fern gullies will proceed once the specialised habitat requirements of the ferns can be met. Native birds and animals have returned to the area naturally or have been deliberately introduced.
Tower Hill - page 2
A Natural History Centre has been established within the crater to inform visitors, several walks have been developed and lookouts built. Signs and informational material within the reserve and on the crater rim lookouts have uneven coverage with heavy emphasis on the restoration project while the volcanic past is generally neglected. The descriptive booklet and the Natural History Centre displays include an excellent explanation of how the crater and cones formed but this is not followed up in signs along the walking tracks. Signs at crater rim lookouts are particularly uneven in coverage; visitors at the lookouts are looking down onto the central scoria cones, the crater lake and the inside of the crater rim but these crucial features are ignored in explanatory signs at the lookouts

Crater lake
Part of the crater lake. The crater wall is on the left, the smaller scoria cones in the middle of the wide crater are on the right.
Tower Hill is beside the Princes Highway about halfway between Port Fairy and Warrnambool (14.5 kilometres west of Warrnambool). The small village of Koroit is on the inland slopes of the crater. The access road into the Reserve turns off the Princes Highway as a one-way road into the Natural History Centre and car park. A road along the eastern rim of the crater goes past a couple of lookouts with views into the crater.

Koala Wallaby
Koalas (left) and wallabies (right) are readily seen in the Tower Hill Reserve.
  "Tower Hill State Game Reserve" by Parks Victoria at - accessed on 25 April 2010
   "Tower Hill State Game Reserve" pamphlet by Fisheries and Wildlife Division Ministry for Conservation, undated.