Volcanoes form when magma escapes through weak points in the Earth's crust called volcanic vents. Magma rises from the mantle through cracks and fills magma chambers, building pressure until an eruption expels ash, lava, and rocks. The deadliest eruption was in 1815 at Mount Tambora in Indonesia, killing over 92,000 from starvation after blotting out the sun. Other deadly eruptions like Krakatoa in 1883 caused thousands of deaths from tsunamis rather than lava or ash. Volcanoes can be active and monitored as explosions risks, dormant if inactive for thousands of years but magma chambers could reactivate them, or extinct with zero eruption risk.

1. Volcanoes

2. What is a volcano? A volcano forms when a weak point in the crust of the earth allows magma to escape the opening is called a volcanic vent. The vent may be a circular hole or crack. Occasionally magma escapes causing an eruption. Some of the materiel erupted creates the hill or mountain the crater is on. http:// www.youtube.com/watch?v =G8ivtashGqE

3. Magma from the mantle rises through cracks in the earths crust and fills the magma chamber. There can be many types of gases made from melted rocks some are more explosive and deadly than others. The gases form bubbles and this builds up pressure. Extreme pressure causes an eruption sending ash, lava and rocks out of the crater. What causes eruptions?

4. What was the most deadly eruption? Tambora Indonesia 1815. This eruption killed a staggering 92,000 more than twice the population of Nelson. The main cause of deaths was not lava or ash but starvation. Other eruptions like Krakatua Indonesia caused 36,000 deaths, those deaths are not the result of lava or ash but a tsunami. Vo lcano Source(s): Cascades Volcano Observatory (USGS) Eruption of Mt Vesuvius Hakone (VRC, ERI, University of Tokyo) MichiganTech Mount Vesuvius Peakbagger.com Philippine Volcanoes US National Report to IUGG, 1991-1994, Reviews of Geophysics Vol. 33 Supplement 1995, Mount Pinatubo, Philippines , © 1995 American Geophysical Union Volcano World

5. Lake Taupo – a peaceful swimming hole or death trap? Is this a place to swim watch the sunset and have a good kiwi summer… Yes, but it didn't use to be it was a massive volcano a caldera. The volcano was so massive the Chinese emperors saw a change of light in the sky way over in China! This volcano could still erupt but has a very low chance of doing so. It is a dormant volcano meaning it hasn't erupted for thousands of years but if the magma chamber fills up it still could erupt.

6. Active, Dormant and Extinct what are they? Active… an active volcano is a volcano that is to be watched it could explode any moment and has exploded in recent history. E.g. White Island Dormant… A dormant volcano has not erupted for thousands of years but still have the potential to erupt if the magma chamber fills up. E.g Mt Taranaki. Extinct… a extinct volcano is past its glory days and has a zero percent chance of erupting. E.g. Mt Eden

7. Thanks to Mums volcanoes folder. Google / wiki. Youtube. Ignite learning. Credits