What is the difference between a supervolcano and a flood basalt eruption? The only thing I’m fairly certain about is that they are both extremely destructive and high-energy events; I have a hunch that flood basalt eruptions are even larger than supervolcanoes.
Are flood basalt eruptions “qualitatitively” different from just an extremely large “regular” volcano?
It seems from this link that supervolcanoes explode like, uh, really big volcanoes while flood basalt kind of gush out of a crack and flood the area with magma, less explodey like.
“Supervolcano” isn’t a technical term, and some people do indeed refer to “large igneous provinces” (i.e. large flood basalts) as a type of supervolcano.
The difference between a Yellowstone-style explosive supervolcano and a large igneous province like the Deccan or Siberian traps is similar to the difference between a Mt. St. Helens style explosive eruption and a Hawaii-style effusive eruption. It mostly has to do with the composition of the magma source, which in turn depends on the tectonic setting. Both Yellowstone and the Deccan traps have been associated with mantle plumes and the eruptive mode depends on what kind of crust the plume is heating. In the case of Yellowstone it’s very thick old continental crust, but the Deccans were probably in a rift zone (also attributed to the plume) with relatively thin crust.
Doesn’t it also have to do with the moisture content (superheated moisture having a tendency to flash to steam when pressure is reduced)?
Xema, it’s a bit more complex than that. One also has to consider the geological matrix involved, as some will permit higher pressures than others.
Supervolcano is NOT a scientific term, it’s a popular press catch all term that has zero constraints or true definition.
A large igneous province may or may not erupt explosively. A Yellowstone type volcano ALWAYS has shown explosive eruptions.
But, at the “end of the day”, which is worse? An igneous province that released 1 billion tons of sulfates, methane, CO2, H2O and ash or the volcano that exploded with a total of the same numbers?
Either way, a large amount of “bad things” are released in a relatively short amount of time, the difference is one time of release of that amount. If it’s spread over centuries, it’s not THAT horrific. If it’s over a year or so or even a day, it’s a BIG deal.
Like people said, supervolcano isn’t a technical term, but using the example of Yellowstone, the difference is the nature of the terrane it’s emplacing in, like GreasyJack said. One of the differences is that Yellowstone likely would have one giant magma chamber, whereas a LIP would have a multitude of feeder pipes/dykes. Also, basaltic magma tends to be much less viscous than the silica-rich types you tend to get erupting after differentiation in a giant chamber.