Questions tagged [volcanology]

The properties and behaviour of volcanoes, from the genesis of magmas to their ascent and emission at the surface of the Earth (or other planetary environments).

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1 answer
46 views

Can a planet have both magma volcanoes and cryovolcanos?

I know that the Jovian ice moons have been speculated to have cryovolcanos. I was thinking of the ice planet of Hoth from Star Wars and in one of the video games; it has regular volcanic activity. ...
5 votes
2 answers
186 views

How does one get a steep-sided stratovolcano with extremely fluid, low-viscosity lava?

The shape of a volcano generally depends strongly on the viscosity of the molten rock used to make it: If the magma/lava ("magva"?) is relatively fluid, it flows out gently, and you get a ...
4 votes
1 answer
66 views

What is the difference between a depleted mantle, and a fertile or enriched mantle?

In a paper about the interior of the Moon, it references depleted mantle sources and enriched mantle sources. Sometimes the latter is referred to as 'fertile'. What is difference between the first two?...
7 votes
1 answer
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Volcanic Explosivity Index of Cumbre Vieja eruption

I have been following the last events of Cumbre Vieja eruption since it started last month. Trying to grasp some basic knowledge of volcanology I have seen the eruption is classified as VEI-3 in the ...
3 votes
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Why on Earth are there observatories on the active Mauna Loa?

Near the summit of Mauna Loa there are two observatories. Mauna Loa is an active volcano that is being watched, so why did they build observatories up there instead of building them on the dormant and ...
8 votes
3 answers
238 views

Is the momentum of a volcano's high-velocity ejecta mostly due to expanding gas?

When I was very young I was always amazed that water didn't come shooting up out of the first ice-fishing hole of the season, due to the weight of all the ice. It doesn't, because the weight of the ...
12 votes
4 answers
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How plausible is it that "a portion of the ocean's floor" could suddenly be "thrown up to the surface" as described in this Lovecraft story?

This question came to me after reading H.P. Lovecraft's "Dagon"- the protagonist has fallen asleep drifting on the ocean in a small boat. He wakes up one morning to discover he's been ...
5 votes
1 answer
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Do sound waves from volcanic eruptions travel around the world?

Do sound waves from volcanic eruptions travel around the world? I recently read about the Krakatoa eruption and how sound waves from that eruption traveled around the globe 4 times and were detected ...
3 votes
1 answer
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For how long can mid-oceanic islands be volcanically active?

The island of St Helena in the South Atlantic was volcanically active for 5 million years, or maybe longer. Is this period of time unusual - which other mid-oceanic islands were active for as long as ...
26 votes
3 answers
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Why is Olympus Mons the largest volcano in the whole solar system?

Why is it that the volcanoes found in the Tharsis Montes region near the Martian equator, (one of which is Olympus Mons) so much larger than those found on Earth. In comparison, Hawaii's Mauna Loa, ...
13 votes
2 answers
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How did CO₂ originate on Earth before there was life?

To start life there has to be $\ce{CO2}$. $\ce{Solar energy + 6CO2 + 6H2O -> C6H12O6 (sugars) + 6O2}$ $C_6H_{12}O_{6} + O_2 \longrightarrow H_2O + {CO}_2 + \text{Energy}$ So to start this cycle, ...
3 votes
2 answers
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Why is felsic (granitic) lava so much more viscous when flowing (or trying to) than mafic (basaltic) lava?

A lower average temperature is, apparently, only part of the answer.... Several sites said composition, not temperature, explains most of the difference... And the difference in viscosity can be up to ...
0 votes
1 answer
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How big were the Siberian Traps originally?

252 million years ago, Siberia was subject to a mass series of flood basalt eruptions, creating a large igneous province called the Siberian Traps. Today, it measures three million square miles (7.77 ...
12 votes
3 answers
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Why are there no volcanoes where continents collide with each other?

I understand that volcanoes occur where oceanic crust is subducted under continental crust such as the Andes. However, they don't occur at places like the Himalayas and Alps where continental crust is ...
8 votes
1 answer
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What determines when the end of a volcanic eruption will happen?

The Cumbre Vieja volcano of La Palma Island, Spain, started to erupt 3 months ago. This week, the volcano stopped emitting lava and there remains only degassing processes. According to this news story,...
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Volcanic Cones - Fissure Type [closed]

Can volcanic cones, similar to the one shown below form from fissure type of volcanoes?
11 votes
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What would be the precursors to a repeated Lake Toba super eruption?

Lake Toba, Indonesia is a supervolcano which was the site of a massive supervolcanic eruption estimated at VEI 8 that occurred 69,000 to 77,000 years ago, representing a climate-changing event. It ...
6 votes
2 answers
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If people aim to reach the mantle, why don't they just use volcano craters?

Once in a while aspiring people aim to drill through the Earth's crust to reach the mantle, but why do they want that when the mantle is actually on or very close to the surface in volcano craters? ...
8 votes
3 answers
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What gases are in the vesicles of pumice?

Many references state that pumice is formed by gases in lava, but I have yet to find a reference of which gases they are. If a piece of pumice floats, then conceivably it still contains the original ...
16 votes
2 answers
326 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 ...
13 votes
3 answers
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If the Bennu asteroid were to hit within a 500 mile radius of Yellowstone National Park, will it trigger a super volcano at Yellowstone?

I am curious to know if it would be highly probable that if the Bennu asteroid were to hit the Earth in 2182, and the point of impact is within a 500 mile radius of Yellowstone National Park, will it ...
24 votes
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How are Mauna Loa $\ce{CO2}$ monthly trends computed?

The problem I am trying to figure out how $\ce{CO2}$ concentration trends are computed in the data provided by the Earth Systems Research Laboratory Mauna Loa Observatory. The data contains monthly ...
3 votes
2 answers
125 views

When did the proto-Himalayas become non-volcanic?

In the normal course of events, when continents move toward each other, at least one coast will be associated with a subduction zone and corresponding volcanic activity. When the Indian subcontinent ...
15 votes
3 answers
561 views

Did the Geothermal Power Plant contribute to Pahoa's Lava Fissures?

There was lava in the area near the wells that the Puna Geothermal Venture facility created. The plant has nine wells that run as deep as 8,000 feet, according to Wil Okabe, managing director for ...
5 votes
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How common are volcanic-induced rain events?

Last year I did an online summer course on remote sensing of volcanoes held by the University of Hawaii at Hilo. During the course, we had a presentation about the monitoring campaign during the 2018 ...
8 votes
1 answer
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What caused a measurable patch of Mt. St. Helens' ash to be deposited across Oklahoma?

Looking at the ashfall distribution map from the 1980 eruption of Mt. St. Helens (below), there is a measured 'patch' of ash depth significant enough to be measured occurring in Oklahoma. What caused ...
8 votes
2 answers
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Similarities and differences between lava flows and fluvial geomorphology (rivers)

How are active lava flows similar to fluvial geomorphology? You can search youtube for these dramatic videos of lava flows, and they all seem to look very similar to streams or rivers. I know that the ...
9 votes
3 answers
853 views

Why do some earthquakes and volcanoes occur within plates?

I know that volcanoes and earthquakes occur on plate margins. But, do some of them also occur within plates?
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1 answer
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How big a risk is Mount Vesuvius for the local population?

How much of a risk does Mount Vesuvius pose for the population of the surrounding area?
5 votes
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161 views

Coral Reef and Volcanic Islands

I have two questions regarding coral reef and volcanic islands. When a new volcanic island is formed, how much time generaly passes before a coral reef starts to form around the island? Another ...
2 votes
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Bouvet Island volcano [closed]

In this remote island (the most remote!) there is a volcano that wikipedia report as inactive, but from google maps there seems to be some ash in the sky. Are there some ongoing eruption?
8 votes
3 answers
452 views

If I could drill a hole into the mantle, would it form a volcano?

Suppose I could drill a hole to mantle at any arbitrary point in the crust, will magma start to rise from the hole and finally become a volcano?
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What is the electrical conductivity of a liquid Komatiite?

I am searching for previous work that has determined the electrical conductivity range for komatiites at the surface. Does anyone have some values or references?
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What is the most current thinking on the amount of heat transferred into the oceans from underwater thermal vents and volcanoes?

My understanding is that with the relatively recent discovery of many more volcanoes on the Mid-Atlantic Ocean Ridge (and perhaps other ocean ridges) and more deep trenches with thermal vents, that ...
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Ranking volcanic rocks influence to geothermal suitability?

I am not a geologist/geology student but I want to quickly know the influence of volcanic rock type to geothermal suitability. I have read read some journals and online articles but it seems there are ...
22 votes
3 answers
23k views

Where can obsidian be found?

Where is obsidian found? Is it typically found on the surface or underground? If underground, how far under (meters or feet would be perfect)? Also, is it found everywhere on Earth, or just in areas ...
2 votes
5 answers
270 views

It is possible to send a probe deep within the Earth?

The deepest borehole ever drilled is just 12km. Consider this as a possibility. A small self-propelled probe is created, its approximately the size of a football, and is very strong, made of materials ...
1 vote
2 answers
67 views

Is it possible for an active volcano to become less violent over time?

Suppose a violent, dangerous composite volcano whose eruptions destroy the nearby countryside exists. Would it be possible for this volcano to change such that future eruptions are less violent, and ...
2 votes
1 answer
227 views

How many extreme shifts in climate has Earth gone through in its existence?

As the Earth formed, it went through cycles of essentially hotter and colder periods. Extremely volcanic times and ice ages, in feedback loops contributing to one another. CO2 swinging from high to ...
1 vote
1 answer
82 views

What happens when a mid-ocean ridge sub-ducts underneath continental crust?

I'm aware that oceanic crust always sub-ducts to continental crust, but surely the geologic forces pushing the ridge apart in the first place isn't just going to turn off, right? Any answers would be ...
3 votes
0 answers
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What if Pinatubo's eruption in 1991 had been followed by a La Niña rather than an El Niño?

If there had been a La Niña rather than an El Niño in 1991-92, would the sulfur aerosol veil caused by the release of 17-20 megatons of sulfur dioxide during the Pinatubo eruption of June 1991 have ...
4 votes
1 answer
81 views

Frost in trees in the middle of summer (of 536)

It was so cold that frost formed inside trees in the middle of summer. Traces of this have been found in Russia, among other places. It is very rare for trees to freeze internally during the summer. ...
5 votes
1 answer
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Employment of Volcanologists and Petrologists

What industries or government departments hire volcanologists and igneous petrologists/geochemists in the United States?
13 votes
1 answer
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Why would volcano eruption cause cardiac arrest?

Following recent eruption of Mt Ontake and the sad news of over 30 people found in 'cardiac arrest', why would the eruption cause it? My initial thought would be that the cause of death would ...
4 votes
2 answers
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Causes of fluctuations in atmospheric oxygen in past 300 Mya

I have two questions based on the history of atmospheric oxygen levels depicted below. Source: https://commons.wikimedia.org/wiki/File:Sauerstoffgehalt-1000mj2.png. The notes below the chart explain ...
1 vote
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Why aren't there ultra acid igneous rocks?

In my study, I found that in volcanoes when the magma is going up it formed different types of rocks. There are basic, acidic and ultrabasic. My question is why isn't there ultra acid igneous rocks ...
19 votes
3 answers
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Is the magma in one volcano different from the magma in every other volcano?

First off, a confession: I'm asking this question because of The Lord of the Rings. If you're not aware already, in the story, a magical ring can only be destroyed in a specific volcano. The reason ...
20 votes
3 answers
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Why does Volcano Lightning occur?

There are many pictures I've seen of lightning coming out of the plume of smoke caused by a volcano (Often called 'Volcano Lightning'). Example: Why does this happen?
1 vote
1 answer
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How does fertile soil reach newborn volcanic islands?

When a volcanic island first surfaces, I assume no vegetation can grow, as it probably only consists of volcanic rock. How would a volcanic island like Iceland that is far from any continent grow to ...

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