Questions tagged [volcanology]

The properties and behaviour of volcanoes.

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11
votes
1answer
861 views

What evidence is there for geological mechanisms that formed the Siberian traps flood basalt?

The Siberian Traps are the modern day remnants of the flood basalt event. Its eruptions is widely believed to be a major contributing factor of the Permo-Triassic extinction event. In reading ...
18
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1answer
262 views

What percent of volcanoes are glaciated?

I have not been able to find an estimate of how many known volcanoes host perennial ice masses, and it would be very useful to me. Does anyone know of any attempts to do this?
11
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1answer
137 views

What is the mechanism behind changes in oxidation state (of iron, for example) as magma rises?

From this answer, I learned that rising magma may change oxidation state, which I wasn't aware of. In [#1], the authors state in the abstract The conventional view holds that the oxidation state ...
11
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1answer
159 views

What efforts have been made to separate the microseismic events related to wind-related ocean waves from the components of volcanic origin?

I have read the question What generates the microseism? and it's accompanying answer. In [#1, cited below], they use the azimuth values of seismographic activity on the flanks of the volcano ...
9
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1answer
139 views

What are the factors that dictate a given topology for seismometer placement around a volcano?

The image below (borrowed from [#1]) shows the topology of the seismometers around the volcano Stromboli. In the text, they explain the following: The seimometers were set on the flanks of the ...
11
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2answers
2k views

Zeolites, odor control, and the witchcraft of sunlight

Various companies offer "volcanic crystals" or "volcanic rock" available in small mesh bags for odor control. The best description I have found is that these are made up largely of Zeolites. All of ...
9
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1answer
348 views

How does the composition of volcanic rock change as it makes its ascent towards the surface?

A schematic for the fluid mechanics of a volcano is represented below. Graciously borrowed from Figure 1 of the reference cited below From the caption of that figure: During explosive eruptions, ...
10
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2answers
1k views

Why are alkali basalts found at rifting centres and on top of 'plumes', whereas MORBs are generally tholeiitic?

So I was essentially wondering why it was that the basalts on top of 'plumes' at 'hotspots' (sometimes called OIBs, ocean island basalts) and at continental rifting centres are enriched in alkaline ...
12
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1answer
71 views

Why are titanium oxides lumped in with magnetite for the purposes of analyzing water bubble nucleation?

I was reading a bit about the fluid mechanics of volcanoes to further understand some of the dynamics of "magma wagging" from my earlier question. From [2]: Heterogeneous nucleation, in which the ...
9
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1answer
335 views

What are these “ship wrecks” (pictured) in the old volcano crater?

They consists of stone, of course, but have strange U cross section, as if they were the remaining of some ships without the head and tail section. Could anyone tell how have they formed? They almost ...
12
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1answer
180 views

How did this rock dome (pictured) form?

I saw this rock formation near Hveravellir, Iceland. It is probably of volcanic origin and looks like a dome. It is nearly symmetric and appears to consist of hardened lava maybe, with several very ...
8
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1answer
86 views

Are there measurement techniques that can help determine the exact geometry of a volcanic vent?

In a previous question What happens to the higher frequency content of the tremors associated with a volcanic eruption?, I asked about the high(er) frequency content of a volcanic eruption. In the ...
11
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1answer
250 views

What happens to the higher frequency content of the tremors associated with a volcanic eruption?

From [1]: The main characteristics of volcanic tremor depend strongly on whether a volcano is erupting explosively and on the intensity of the event. Long before an eruption, tremor is ‘narrow-...
16
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1answer
434 views

Why won't Yellowstone explode?

From my understanding Yellowstone is a massive super-volcano, so why isn't it active? Where has its (correct me if I'm using the wrong term) hot-spot gone? Can it still erupt?
7
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1answer
157 views

Is there an earth science discipline, or subdiscipline, that only studies magma or lava?

I know volcanologists study volcanoes. Is there a subdiscipline that only studies maga or lava? A magmatologist?
11
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1answer
1k views

How does the sand appear on Hawaiian beaches

It's quite surprising to me that there's only one beach with black sand on Hawaii (maybe not exactly one beach, but it's only a very small fraction). The concern is, if the whole Hawaii is volcanic, ...
10
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1answer
1k views

Why do Volcanoes give out so much Sulphur Dioxide and Carbon Dioxide?

From my understanding, the mantle is in a highly reduced state, so I can't understand why a volcano would give off a highly oxidised gas such as sulphur dioxide. Carbon dioxide is too an oxidised ...
11
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1answer
2k views

Determining a rock age using volcanic ash layer

I wanted to know if volcanic ash deposits found in the geologic record are most useful in correlating the age of rock layers if the volcanic ash was distributed over a large area during a short period ...
15
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6answers
710 views

Does volcanic activity fluctuate?

According to this person's surmises, volcanic activity appers to be increasing. However, according to this report, volcanic activity is probably not increasing. My question is: Does Volcanic activity ...
10
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2answers
260 views

Is it possible to find the magma chambers that produce supervolcanos?

Supervolcanos have occurred in the recent geological past, but not within the past 74,000 years. Is it possible to find the magma chambers with no previous history of supervolcanic activity that are ...
11
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1answer
485 views

Are mantle plumes distributed around the core randomly or in a known pattern?

Background: The theory of mantle plumes is useful (although controversial) in explaining the occurrence of intra-plate volcanoes. The website here suggests that "hotspots" exist in fixed locations ...
8
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1answer
781 views

What is the most powerful natural catastrophic event on record?

Natural catastrophic events such as hurricanes, earthquakes, volcanic eruptions and meteor impacts releases vast amount of energy. What is the most powerful single event of such nature ever recorded ...
12
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1answer
240 views

How do mantle plumes travel from the core of Earth to the crust?

As mantle plumes begin in the core and move towards the crust, I would have thought that the heat in the mantle plume would disperse to the surrounding mantle, and the plume would cease to exist by ...
28
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4answers
1k views

Can pyroclastic flows cross water?

While reading the Wikipedia article on pyroclastic flows, I noticed that there's a section called 'Interaction with water'. This piqued my interest, as I was under the impression that lava generally ...
21
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2answers
380 views

What are some of the strongest theories against the existence of mantle plumes?

Among the people I interact with in the geodynamics community, it seems that almost all of us are in full support of the mantle plume theory. What are the strongest arguments against this theory? Is ...
8
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1answer
962 views

What causes a volcano? [closed]

Inspired by the question, How does one measure what causes earthquakes?, I'd like to know what causes another great geological phenomenon - volcanoes?
13
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1answer
1k views

Why does the “Ring of Fire” pretty much define “Pacific Rim”

The Pacific Rim is pretty much defined by the so-called "Ring of Fire." It consists of the "stomping ground" for a disproportionate number of earthquakes and volcanoes, and the affected territory ...
11
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1answer
415 views

Is the Yellowstone National Park unique for its geysers?

The Yellowstone National Park in Wyoming is unique for its large number of "thermal occurrences, of which there are some 30 geysers. This, in turn, appears to be the result of the presence of large ...
24
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1answer
641 views

Why did the Laki eruption of 1783 produce so much fluorine?

The Laki fissure eruption of 1783/4 in Iceland was not particularly large or explosive, but it is infamous for the large quantities of fluorine (or hydrofluoric acid) and SO2 that it produced, and the ...
14
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3answers
1k views

Why is there a line of volcanoes along the northwest coast of North America?

Mount Hood in Oregon is a dormant volcano, and in Washington Mount St. Helens and Mt. Ranier are both active volcanoes. What causes this line of volcanoes running parallel to the coastline along the ...
9
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0answers
104 views

Any other fumarolic ice caves in the literature? [closed]

I study the fumarolic ice caves of Erebus Volcano, and am looking for published research on similar sorts of caves. My criteria for a "fumarolic ice cave" are that it must be: A gas-filled void space ...