A Quick Quiz
If you can answer the questions below you probably don ’ t need to read this trip report . If you get a number of the answers wrong then there is a whole lot of history about our state that you were never taught at school . I would suggest you look out for the next time Sue and Brian run this trip and register quickly :
� How many volcanoes have erupted between Geelong and Mt Gambier ? Most people guess between 5 to 15 . The correct answer is at least 400 . Yep that ’ s right at least 400 . This makes western Victoria the 3 rd largest volcanic plain in the world ! And the region is dormant not extinct .
� Were there any active volcanoes between Geelong and Mt Gambier during aboriginal habitation of the area ? Absolutely Yes ! Mt Gambier is the last volcano to erupt on mainland Australia and it erupted just 4,500 years ago and would have been witnessed by the indigenous people . There are a number of volcanoes that have erupted in this region during the aboriginal peoples 40,000 years in Australia . Note : the volcanoes in the region range from 4,500 years old to about 2 million years old . So only some were seen by indigenous peoples .
� Why is the Geelong to Mt Gambier volcanic area different to most other volcanic areas of the world ? Most volcanos erupt 1 ) along the lines where the earth ’ s tectonic plates crash into each other or 2 ) are formed above “ hot spots ” under the earth ’ s crust . Western Victoria ’ s volcanos aren ’ t formed by either of these . There is some new theories being developed to try to explain how Victoria ’ s volcanoes were formed . Penshurst Volcano Discovery Centre explained the theory very well .
� How many different types of volcanoes does Western Victoria have ? There are 3 main types : Lava ( Shield ) volcanoes , Maar volcanoes and Scoria Cones . We also found out about this at the Penshurst Volcano Discovery Centre which enabled us to identify the different types as we were travelling around the region . BTW , Tower Hill near Warrnambool is one of the largest maar volcanoes in the world ( and yes Brian and Sue took us there too ) .
� Are there any lava tunnels in this volcanic area ? You bet yah . Not as big as the Undara Lava Tubes in Qld but we do have some smaller one in Victoria . ( See photo below or Google “ Byaduk Caves ”).
� What are Tumuli ? And what makes them rare ? Tumuli are circular mounds of medium sized rocks The mounds are about 10m high and 20 m across . They were created when lava ( from Mt Napier ) flowed through a lava tunnel but the pressure caused lava to ooz out in places along the ceiling of the caves . There are only 3 places on earth where Tumuli are found . Another winner for Victoria . ( See photo below for an example ).
� How much ground was eventually covered by lava between Geelong and Mt Gambier ? Ans : Being one of the largest volcanic plain in the world it must be big , right . Well its actually 23,000 square kilometers ! Yes there was a lot of lava that flowed out of the volcanoes over millions of years .
� We have all seen the amazing dry rock walls around the Camperdown area . How many different types of wall were constructed ? We found 5 different types ; varying in 1 ) construction methods , 2 ) heights and 3 ) purpose for which they were built . One type was even built to keep out rabbits !