crater shapes

[ammonium nitrate]

i'm trying to work out why it is that different volcanoes have different shaped craters and volcanoes even though they have approximately the same ash output, suggesting an equally violent eruption, for example in one period of volcanic activity, mt eden produced approximately the same volume of material during eruptions as mt mangere, yet mt mangere has a dual crater, neither of them evenly shaped or sized while mt eden is has a deeper crater which is perfectly even in shape and size, the domain produced approximately the same volume as mt albert, yet neither volcano has a notable crater and the domain does'nt even have much of a slope, mt smart produced approximately the same amount of material as pupuke, which is now a caldera, meanwhile the big king produced about as much as mt eden, yet is much smaller than mt eden and does not have a pronounced crater, what is the cause of this?

[Moontanman]

i'm trying to work out why it is that different volcanoes have different shaped craters and volcanoes even though they have approximately the same ash output, suggesting an equally violent eruption, for example in one period of volcanic activity, mt eden produced approximately the same volume of material during eruptions as mt mangere, yet mt mangere has a dual crater, neither of them evenly shaped or sized while mt eden is has a deeper crater which is perfectly even in shape and size, the domain produced approximately the same volume as mt albert, yet neither volcano has a notable crater and the domain does'nt even have much of a slope, mt smart produced approximately the same amount of material as pupuke, which is now a caldera, meanwhile the big king produced about as much as mt eden, yet is much smaller than mt eden and does not have a pronounced crater, what is the cause of this?

 

 

I'm gonna have to ask why would you expect craters to be the same?

[ammonium nitrate]

I'm gonna have to ask why would you expect craters to be the same?[quote]

 

its the physics behind it, a similar volume of material ejected from two volcanoes during a single eruption suggests that the violence of the eruption would be similar, which implies that the mark they eave would also be similar, im just trying to work out why they are not

Edited October 27, 2012 by ammonium nitrate

[Moontanman]

I'm gonna have to ask why would you expect craters to be the same?

 

its the physics behind it, a similar volume of material ejected from two volcanoes during a single eruption suggests that the violence of the eruption would be similar, which implies that the mark they eave would also be similar, im just trying to work out why they are not

 

 

No, the initial conditions are different for each and every volcano, from the makeup of the lava to the conditions of the earth's crust in that location. I would be highly surprised if any crater was the same as any other crater, volcanic or otherwise...

[ammonium nitrate]

even when the volcanoes in question are mono genetic such as all the ones mentioned above? wouldn't that mean they had similar propertys of magma and such like?

[Acme]

Volcanic eruptions are dynamic complex events subject to many variables. For example, geologists studying Mt. St. Helens had no past evidence to suspect a lateral blast as occured in 1980. St. Helens has in the past had pyroclastic eruptions as in 1980, but from the summit, as well as eruptions of flowing lava similar [though of different chemistry] to those in say Hawaii. see Eruptive History of Mt. St. Helens

 

Many factors come into play in an eruption such as the character of the overburden from past eruptions, the amount of water and relative amounts of minerals in the melt, and the volume, temperature and shape of the magma chamber to name a few. One would not reasonably expect the same shape crater from any two eruptions from the same or different volcanoes any more than to expect two windows to break the same even if the same stone were thrown at them.

[ammonium nitrate]

ok then, so while we are on the subject of volcanic eruptions, what is the statistical likely hood of an eruption in a dormant volcano?

[zapatos]

ok then, so while we are on the subject of volcanic eruptions, what is the statistical likely hood of an eruption in a dormant volcano?

100%

 

A dormant volcano is expected to erupt again. If it doesn't erupt again then it was mislabeled, and should have been catergorized as extinct.