Yes, Australia does have volcanoes, but whether they are active depends on where one looks and how the term “active” is defined. The Australian mainland is not home to any currently erupting volcanoes, nor has it been since European settlement. Numerous volcanic structures exist across the continent, classified mostly as extinct or dormant, indicating they retain the potential to erupt again. The nation’s active volcanoes are located in remote, sub-Antarctic external territories, thousands of kilometers from the mainland.
The Status of Mainland Australia’s Volcanoes
Mainland Australia’s volcanoes are generally classified as either extinct or dormant. A volcano is considered extinct if it has not erupted in the last 10,000 years and is not expected to erupt again. In contrast, a dormant volcano has not erupted recently but still shows signs of activity or is located in a region where future eruptions remain possible.
The most recent volcanic activity on the mainland is centered in the Newer Volcanics Province (NVP) of southeastern Australia. Here, the most recent eruption occurred at Mount Gambier in South Australia, with geological evidence suggesting this event took place approximately 4,300 to 5,000 years ago. Because this time frame is within the 10,000-year window, these volcanoes are viewed by many geologists as dormant rather than extinct.
Although thousands of years have passed since the last event, this relative geological youth means the region is considered a potentially active volcanic field. The probability of an eruption remains very low, but the area is known to be capable of generating future monogenetic volcanoes, which are small volcanoes that erupt only once. Most other ancient volcanic sites across the continent, such as those in New South Wales and Queensland, ceased activity millions of years ago, rendering them extinct.
Location and Geological Mechanism
The Newer Volcanics Province (NVP), the primary area of recent volcanism in Australia, stretches across western Victoria and into the southeast of South Australia. This extensive field covers over 23,000 square kilometers and contains more than 400 individual volcanic centers. The NVP is characterized by monogenetic volcanoes, meaning each eruption center typically produced a single, short-lived event, unlike the composite volcanoes found at plate boundaries.
The existence of this volcanism is unique because Australia sits centrally on the Indo-Australian tectonic plate, far from any plate boundaries where most of the world’s volcanoes occur. This activity is therefore an example of intraplate volcanism, driven by processes occurring within the plate itself. The prevailing scientific explanation involves upwelling of hot material from the upper mantle, likely triggered by a mechanism known as edge-driven convection (EDC).
This process occurs where the Australian continental lithosphere abruptly thins at the continental edge. This variation in thickness can induce small-scale convective instabilities in the underlying mantle. This localized upward movement of hot, hydrated mantle material, combined with tectonic forces that create decompression in the crust, allows magma to form and rise to the surface through crustal faults. This mechanism explains why volcanism is concentrated in this specific region of southeastern Australia.
Active Volcanoes in Australian External Territories
While the mainland is quiescent, Australia governs active volcanoes located far from the continental mass in its external territories. These are found on Heard Island and the nearby McDonald Islands, situated over 4,000 kilometers southwest of Perth in the Southern Ocean. These islands form part of the Kerguelen Plateau and are the result of a long-lived mantle plume, or hotspot, which is a different geological mechanism than the one responsible for the mainland’s NVP.
Heard Island is dominated by the stratovolcano known as Big Ben, which rises to Mawson Peak, the highest point under Australian sovereignty outside of the Antarctic territory. Big Ben has shown frequent activity since the mid-1980s, with observed lava flows and steam emissions. The McDonald Islands, located 43 kilometers away, have also been volcanically active, with eruptions in the 1990s and early 2000s causing the main island to increase in size.
This ongoing activity distinguishes these distant islands as Australia’s only volcanic hazards. Their remote location means they pose no threat to the Australian mainland population, but they serve as a clear example of active volcanism within Australian territory. The ongoing eruptions make these islands valuable to scientists studying plume-type volcanism.
Volcanic Landscapes and Geological Legacy
The legacy of Australia’s past volcanism is visible in many landforms across the southeast, particularly within the Newer Volcanics Province. The region is defined by an extensive, flat to undulating basaltic plain, one of the largest in the world, formed by ancient lava flows. Rising above this plain are numerous small, conical hills known as cinder cones or scoria cones, such as Mount Elephant and Mount Napier.
Another common feature is the presence of maars, which are broad, low-relief volcanic craters formed by explosive eruptions that occur when rising magma interacts violently with groundwater. Mount Gambier, with its four crater lakes, is a well-known example of this type of feature. The magma’s interaction with the extensive groundwater system of the region created these water-filled depressions.
Beyond the visible cones and craters, ancient lava flows left behind features like lava tubes and lava caves, such as the Byaduk Caves in Victoria and the Undara Lava Tubes in North Queensland. These subterranean features were created when the surface of a lava flow cooled and hardened while the molten rock beneath continued to flow, draining out to leave a hollow tunnel. These volcanic landscapes have shaped the region by providing rich, fertile soils for agriculture and are often preserved in national parks.