Active volcanoes

Active volcanoes are those that are currently erupting or showing signs of unrest, such as unusual earthquake activity or significant new gas emissions.Regularly active volcano ejected lava, ash, smoke and other substances. With a very active volcano this happens almost constantly. In the other between the eruption extended weeks or months.
While there is evidence of volcanic activity in the past, a lot of volcanoes are active today. They’re bubbling with lava, spewing ash and triggering earthquakes as you sit in class.Explosive eruptions can shoot columns of gases and rock fragments tens of miles into the atmosphere, spreading ash hundreds of miles downwind.
While some of the volcanoes are dormant for hundreds of years, others who were believed to be extinct, become active again, as happened 1973rd with Helgafelom (Hajmej, Iceland).

Alaska is home to 41 historically active volcanoes stretching across the entire southern portion of the State from the Wrangell Mountains to the far Western Aleutians. An average of 1-2 eruptions per year occur in Alaska.

Mount Etna, the largest active volcano in Europe, reaching 3,350 m and covering a surface of about 1,260 km2, started its activity at about 600 ka, after the end of  Upper Pliocene to Pleistocene subaqueous and subaerial eruptions at the northwestern edge of the Iblean Plateau. Mt.
The New Zealand area is characterised by both a high density of active volcanoes and a high frequency of eruptions.

The largest volcanic eruption of the 20th century occurred at Novarupta Volcano in June 1912. It started by generating an ash cloud that grew to thousands of miles wide during the three-day event.
Some volcanoes expel gas and burning lava in the terrifying outbursts. Others have explosive eruptions and expel clouds of ash and gas.Volcanoes are evidence that the Earth is restless, especially within the crust and upper mantle.

If you live near an active or dormant volcano, you should be prepared to evacuate at a moment’s notice, as eruptions are not always predictable.Volcanoes can be incredibly destructive to buildings and dangerous to your family. In addition to the direct hazards, an eruption can be accompanied by landslides, mudflows, flash floods, earthquakes and tsunamis.