Lava Creek Eruption (Yellowstone Caldera) Volcano Explosivity Index (VEI): 8 Some volcanic eruptions are explosive and others are not. When this type of magma erupts, it flows out of the volcano. If strong enough, underwater volcanoes can cause tsunamis. The deadliest and biggest volcanic eruption in recorded history was the eruption of Mt.Tambora which … People should know that before a volcano erupts there are warning signs such as rumbling sounds, continuous… Many scientists believe that 80% of the Earth’s volcanic eruptions actually take place underwater (in the ocean). Volcanic eruptions happen with early warnings unlike earthquakes that are sudden. In the years before the 1883 eruption, seismic activity around the Krakatoa volcano was intense, with earthquakes felt as far away as Australia. There are early warning signs before a volcano erupts so there is at least time for residents around the volcano to prepare before the actual eruption occurs. Volcanic eruptions happen with early warnings unlike earthquakes that are sudden. A good example is the eruptions at Hawaii’s volcanoes. Villarrica, one of Chile's most active volcanoes, looks a little different after a violent eruption on March 3, 2015. Volcanic eruptions can result in additional threats to health, such as floods, mudslides, power outages, drinking water contamination, and wildfires. There are early warning signs before a volcano erupts so there is at least time for residents around the volcano to prepare before the actual eruption occurs. https://news.yale.edu/2013/09/11/volcano-erupts-violently-warning-signs A large eruption occurred at Pinatubo on June 12, sending up a cloudy plume that reached an altitude of nearly 12 miles (19 km). Before the 1815 eruption, Mount Tambora was 14,000 feet (4.3 kilometers) tall and was reduced down to 9,000 feet (2.7 kilometers) after the eruption. The explosivity of an eruption depends on the composition of the magma. A caldera is a very large crater that forms after a very large Early phase. If magma is thin and runny, gases can escape easily from it. Note that there may be many other eruptions that have not been identified, and estimates for the size of eruptions can be subject to considerable uncertainties. Health concerns after a volcanic eruption include infectious disease, respiratory illness, burns, injuries from falls, and vehicle accidents related to the slippery, hazy conditions caused by ash. This is a list of volcanic eruptions of the 20th century measuring a Volcanic Explosivity Index (VEI) of at least 4, as well as notable smaller eruptions.