Search results
Results from the WOW.Com Content Network
Tephra is a generalized word for the various bits of debris launched out of a volcano during an eruption, regardless of their size. [4] Pyroclastic materials are generally categorized according to size: dust measures at <1/8 mm, ash is 1/8–2 mm, cinders are 2–64 mm, and bombs and blocks are both >64 mm. [5] Different hazards are associated with the different kinds of pyroclastic materials.
Some volcanoes have undergone catastrophic eruptions, killing large numbers of humans or other life forms. This list documents volcanic eruptions by human death toll. This list documents volcanic eruptions by human death toll.
A wide variety of volcanic processes can produce tsunamis. This includes volcanic earthquakes, caldera collapse, explosive submarine eruptions, the effects of pyroclastic flows and lahars on water, base surges with accompanying shock waves, lava avalanching into the sea, air waves from explosive subaerial eruptions, avalanches of cold rock, and avalanches of hot material. [1]
It’s possible for volcanoes to have a short-term impact on the climate – including global temperature cooling – due to the gases they inject high into the upper atmosphere.
On Earth, volcanoes are most often found where tectonic plates are diverging or converging, and because most of Earth's plate boundaries are underwater, most volcanoes are found underwater. For example, a mid-ocean ridge , such as the Mid-Atlantic Ridge , has volcanoes caused by divergent tectonic plates whereas the Pacific Ring of Fire has ...
As plate movement starts to carry the volcanoes away from their eruptive source, eruption rates start to die down, and water erosion grinds the volcano down. The final stages of eruption cap the seamount in alkalic flows. [55] There are about 100,000 deepwater volcanoes in the world, [56] although most are beyond the active stage of their life ...
One of the world's best-preserved mineralized calderas is the Sturgeon Lake Caldera in northwestern Ontario, Canada, which formed during the Neoarchean era [14] about 2.7 billion years ago. [15] In the San Juan volcanic field , ore veins were emplaced in fractures associated with several calderas, with the greatest mineralization taking place ...
During the same time interval, CO 2 emissions from volcanoes during eruptions were estimated to be 1.8 ± 0.9 Tg per year [10] and during non-eruptive activity were 51.3 ± 5.7 Tg per year. [10] Therefore, CO 2 emissions during volcanic eruptions are less than 10% of CO 2 emissions released during non-eruptive volcanic activity.