<Tr> <Td> 8 </Td> <Td>> 25 km (16 mi) </Td> <Td> 1,000 km (200 cu mi) </Td> <Td> Supervolcanic </Td> <Td> 50,000 + years </Td> <Td> Lake Toba (74 k.y.a.) </Td> </Tr> <Tr> <Td_colspan="6"> * This is the minimum eruptive volume necessary for the eruption to be considered within the category . * * Values are a rough estimate . They indicate the frequencies for volcanoes of that magnitude OR HIGHER † There is a discontinuity between the 1st and 2nd VEI level; instead of increasing by a magnitude of 10, the value increases by a magnitude of 100 (from 10,000 to 1,000,000). </Td> </Tr> <P> Magmatic eruptions produce juvenile clasts during explosive decompression from gas release . They range in intensity from the relatively small lava fountains on Hawaii to catastrophic Ultra-Plinian eruption columns more than 30 km (19 mi) high, bigger than the eruption of Mount Vesuvius in 79 that buried Pompeii . </P> <P> Hawaiian eruptions are a type of volcanic eruption, named after the Hawaiian volcanoes with which this eruptive type is hallmark . Hawaiian eruptions are the calmest types of volcanic events, characterized by the effusive eruption of very fluid basalt - type lavas with low gaseous content . The volume of ejected material from Hawaiian eruptions is less than half of that found in other eruptive types . Steady production of small amounts of lava builds up the large, broad form of a shield volcano . Eruptions are not centralized at the main summit as with other volcanic types, and often occur at vents around the summit and from fissure vents radiating out of the center . </P>

Where do volcanic eruptions generally occur give one example