Avoid driving during and after ash fall when visibility can be very low and roads are slippery. Protect your lungs and eyes by wearing protective gear such as goggles and masks.
Pay particular attention to vulnerable people and support them to evacuate or shelter in place. Follow official instructions from local authorities on whether to evacuate or take shelter. If you get warning prior to ash fall, return home from school or work and shelter in place. If the ash fall is heavy, do not remain in a building that has a low-pitched or flat roof. Make sure you have additional supplies such as dust masks, eye protection, cleaning supplies, a flashlight and an evacuation bag to hand.
Collect and store clean water and clean up outside carefully when it is declared safe to do so. Key hazard-specific messages for individuals and communities on how to prepare for, and stay safe during, volcanic eruptions.
Read more. Do you know how to prepare for a volcanic eruption? Assess and plan Reduce risks Prepare to respond. They lowered the volcanic alert status to Level o background and declared that Tongariro was back asleep even if some steam might persist from the Te Maari vent.
However, it is surprising for most people to hear that there are no hard-and-fast definitions for what a volcano is considered active, dormant or extinct.
Many times, what one person might think is an extinct volcano might actually merely be dormant and that transition is shades of grey, anyway. So, how do I differentiate between active, dormant and extinct volcanoes. This is my personal take with input from the volcanological community and to me, it's all about potential.
If you have a different definition, feel free to leave that in the comments. Active: This one is easy Any volcano that is erupting is considered active. That's a no-brainer.
The USGS definition mentions that any volcano that has erupted during historic times could be considering "active". That last category I tend to call "potentially active" and grades into "dormant" as they might not be showing any signs of current volcanic active above or below the surface. So, volcanoes like Kilauea or Sakurajima or Cotopaxi are active. If there are clues that magma is on its way and an eruption might be in the works, that volcano is active.
Active volcanoes generally occur close to the major tectonic plate boundaries. They are rare in Australia because there are no plate boundaries on this continent. However, there are two active volcanoes located kilometres south west of Perth in the Australian Antarctic Territory: Heard Island and the nearby McDonald Islands. Gas-rich sticky magmas dominate the Asia Pacific, making composite volcanoes and calderas the most common varieties in the region. These types of volcanoes severely threaten lives, property, agricultural lands and lifelines throughout south east Asia and the Australian region.
Evidence for volcanism throughout geological time can be found in every Australia state and territory, with extensive volcanism down the east coast during the past 60 million years. This volcanic activity can be divided into areas where large amounts of lava flowed from dykes and pipes over a wide area and others where volcanism was produced from either a single central vent or a cluster of vents.
It is thought that the central volcanoes were produced as the Australian continent moved over a hot spot in the underlying mantle which melted through the plate to form the volcano. As the continent moved northward, the stationary hot spot formed volcanoes further to the south on the continent. As a result, the rocks of central volcanoes down the east coast become younger as you move southward. Understanding how volcanoes work and how their eruptions can be predicted is essential for the well-being and preservation of people who inhabit volcanically vulnerable areas.
Eruptions can occur without any preceding signals, making them extremely difficult to predict. However, sometimes there are useful clues for judging when a volcano is likely to erupt. A volcano's eruptive history can provide some clues. However, because only a small number of the world's volcanoes have a known history it is extremely difficult to predict future eruptions, particularly for certain types of volcanoes. Scientists use the repose period, or the time between eruptions, to indicate the expected size and strength of an eruption.
Consistently long repose periods may indicate that a volcano's eruptions are usually large and explosive. However, sometimes there is no clear relationship in the length of time between eruptions and the nature of the eruptions.
Earthquake activity around a volcano can provide valuable information. An eruption can be preceded by hundreds of small earthquakes know as earthquake swarms. Earthquakes also can indicate that magma is moving beneath a volcano. However, eruptions can occur with no perceivable change in seismic activity.
Small changes in the shape of a volcano such as bulging may indicate that magma is rising. Accurately measuring the summit and slopes of a volcano is one of the most important tools used for forecasting an eruption.
Temperature changes in surface lakes or the groundwater near a volcano also can be a valuable early detection tool, although not all large changes in temperature are related to volcanic eruptions. Gases emitted at, or near a volcano may show that a magma chamber is refilling or that a new type of magma is rising from depth. Changes in the volume or type of volcanic gases produced also may be an indicator of magma activity. Mainland Australian currently has no active volcanoes; therefore, Geoscience Australia's work in reducing volcano risk to the community is in support of the work coordinated by the Department of Foreign Affairs and Trade.
In particular, Geoscience Australia uses its expertise to help countries in the Asia-Pacific to mitigate the effects of volcanic eruptions through:. Three common volcano forms are: Shield volcano Shield volcanoes have a broad, flattened dome-like shape created by layers of hot and runny lava flowing over its surface and cooling.
Composite volcano Strato Also known as strato-volcanoes, composite volcanoes are formed from explosive eruptions. Caldera volcano These volcanos erupt so explosively that little material builds up near the vent. Spreading plate margins Areas of the Earth where plates move away from each other are called spreading or divergent plate margins.
Subducting plate margins At subducting plate margins, one plate is pushed under a neighbouring plate as they squeeze together. Hotspot volcanoes Locations of anomalous volcanism i. There are two currently debated explanations of how this volcanism is generated: from hot mantle upwellings or plumes which rise from great depth hence the term 'hot spot' from passive rising of melt from shallow depths that is not actually anomalously hot.
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