Search results
Results from the WOW.Com Content Network
In volcanology, an explosive eruption is a volcanic eruption of the most violent type. A notable example is the 1980 eruption of Mount St. Helens. Such eruptions result when sufficient gas has dissolved under pressure within a viscous magma such that expelled lava violently froths into volcanic ash when pressure is suddenly lowered at the vent.
Types of volcanic eruptions. Some of the eruptive structures formed during volcanic activity (counterclockwise): a Plinian eruption column, Hawaiian pahoehoe flows, and a lava arc from a Strombolian eruption. Several types of volcanic eruptions —during which material is expelled from a volcanic vent or fissure —have been distinguished by ...
This is a list of volcanic eruptions in the 21st century with a volcanic explosivity index (VEI) of 4 or higher, and smaller eruptions that resulted in fatalities, significant damage or disruptions. As of 3 September 2024, the largest volcanic eruption of the 21st century is the 2022 Hunga Tonga–Hunga Haʻapai eruption and tsunami, and the ...
A volcanic eruption could just be a simple outpouring of material onto the surface of a planet, but they usually involve a complex mixture of solids, liquids and gases which behave in equally complex ways. [3] Some types of explosive eruptions can release energy a quarter that of an equivalent mass of TNT. [18]
The most famous and destructive historical eruptions are mainly of this type. An eruptive phase can consist of a single eruption, or a sequence of several eruptions spread over several days, weeks or months. Explosive eruptions usually involve thick, highly viscous, silicic or felsic magma, high in volatiles like water vapor and carbon dioxide.
The volcanic explosivity index (VEI) is a relative measure/prediction of the explosiveness of volcanic eruptions. It was devised by Christopher G. Newhall of the United States Geological Survey and Stephen Self in 1982. Volume of products, eruption cloud height, and qualitative observations (using terms ranging from "gentle" to "mega-colossal ...
There are many different types of volcanic eruptions and associated activity: phreatic eruptions (steam-generated eruptions), explosive eruptions of high-silica lava (e.g., rhyolite), effusive eruptions of low-silica lava (e.g., basalt), sector collapses, pyroclastic flows, lahars (debris flows) and volcanic gas emissions. These can pose a ...
Strombolian eruptions consist of ejection of incandescent cinders, lapilli, and volcanic bombs, to altitudes of tens to a few hundreds of metres. The eruptions are small to medium in volume, with sporadic violence. This type of eruption is named for the Italian volcano Stromboli. The tephra typically glows red when leaving the vent, but its ...