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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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 ...
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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 ...
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5 votes
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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 ...
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Volcanic Cones - Fissure Type [closed]

Can volcanic cones, similar to the one shown below form from fissure type of volcanoes?
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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 ...
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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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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 ...
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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? ...
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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 ...
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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 ...
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7 votes
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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 ...
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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 ...
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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 ...
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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 ...
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2 votes
0 answers
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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?
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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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1 vote
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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 ...
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2 votes
5 answers
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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 ...
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1 vote
2 answers
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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 ...
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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 ...
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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 ...
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26 votes
3 answers
5k views

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, ...
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4 votes
1 answer
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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. ...
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1 vote
2 answers
134 views

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 ...
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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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6 votes
2 answers
285 views

Geomorphological feature identification

I was studying a satellite map of Iceland and came across an interesting, but unnamed feature located between Vatnajökull glacier and Trölladyngja volcano (between 64°50'35"N, 17°11'21"W and 64°48'33"...
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What initiates the plumes which create oceanic hot spots? [duplicate]

What causes the large and very long lasting magma plumes which rise up from the mantle and create a hot spot such as the ones which built the island chains of Hawaii and Galapagos? The volcanic ...
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1 vote
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Did people trigger the White Island 2019 eruption? [duplicate]

I am writing an essay about White Island’s 2019 eruption, and I need to know if the eruption was directly triggered by people. Is it possible that it was? Whether it being quarrying, too much tourism ...
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4 votes
2 answers
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What is the difference between mobile & molten rock?

In the book Fundamentals of Geomorphology (Routledge Fundamentals of Physical Geography) by Richard John Huggett there is a sentence " Intruded rocks, which must be mobile but not necessarily molten,...
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How Can Adjacent Parts of an Oceanic Plate be Subducted in Different Directions?

It is claimed by some that the reason for gaps in chains of volcanoes generated by plate subduction is that some parts of the plate dive deep into the mantle and generate magma plumes, while other ...
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8 votes
3 answers
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Gaps in locations of volcanos (Peru & Chile)

The figure below is taken from Reath, K. et al. (2019) A couple of things can be seen from this representation Volcanism seems to be strongly correlated with subduction zones, in this case the Nazca ...
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1 vote
1 answer
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How likely is Earth to naturally reverse climate change in the next 2 decades?

A new decade question: given that the “mini ice ages” were triggered by volcanic activity, how likely is it that we will experience similar levels of volcanic activity over the next 20 years? In ...
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2 votes
1 answer
150 views

Could Rumblings From Plutons be as Ominous as Rumblings From Volcanoes?

Mount Kinabalu in North Borneo is a 10 million year old pluton. A pluton is a magma plume from the mantle which was not able to reach the surface and erupt as a volcano, but solidified underground and ...
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2 votes
2 answers
116 views

Large Igneous Provinces are like Lunar Mare?

Would Large Igneous Provinces like the Deccan Traps have looked like ancient lunar Mare from space? Glowing lava oceans shinning in the night? Are these two things similar in nature? Would smoke from ...
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6 votes
2 answers
371 views

How is climate change today different than the climate change that ended the ice age(s)?

Someone I know posted a question about climate change that I do not know how to answer. While I do believe (for lack of better word) in climate change, I do not know how to answer this persons ...
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1 vote
0 answers
18 views

Do overlying strata subside before/during volcanic exogenous dome emplacement?

Is subsidence (graben faulting) expected before/during a volcanic exogenous dome emplacement on the surrounding strata?
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7 votes
2 answers
85 views

Why do (some) silicic bodies behave effusively instead behaving explosively as in common?

We encounter dacitic/rhyolitic melts generally in explosive volcanic events. But some of them behave as effusive dome flow. Why do some silicic bodies behave effusively?
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5 votes
4 answers
632 views

Are the cores of every mountain range igneous?

Every volcano is a mountain, but not every mountain is a volcano. Still, it strikes me that--at least for the mountain ranges I can think of in this moment--they all seem to have igneous cores. Is ...
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0 votes
1 answer
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Q: Is the crust getting thinner or is the mantle getting smaller

Volcanoes spit out magma onto the surface of the crust or crevices on the surface, but the magma comes (in effect) from the mantle right? If that's the case, isn't the mantle turning into the crust by ...
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5 votes
3 answers
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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 ...
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3 votes
1 answer
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What determines the scale of columnar jointing?

What physical parameters determine the scale of columnar jointing? What makes the columns thinner or thicker? What makes them taller or shorter? What causes the variation in a given site? What ...
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2 votes
1 answer
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How far a andesitic lava can flow and what is the speed?

For an effusive volcanic activity how far a andesitic lava can flow? What is the speed? Eruption amout 0.2 cubic km amount with 25 degree slope.
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1 vote
0 answers
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Interpreting an outcrop of a thick pure silica bed in a volcanic setting

How can a nearly pure silica bed with 250 m x 50 m x 1.5 m dimensions be interpreted in a volcanic/pyroclastic setting? Here is a photo of it.
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3 votes
1 answer
83 views

Can volcanic gases be emitted in any other way besides volcanic eruptions

What other sources of volcanic gas emissions can there be on earth?
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0 votes
1 answer
282 views

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 ...
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2 votes
1 answer
74 views

Why are pyroclastic flows ground-bound?

This bugged me for a while: Pyroclastic flows are fast (up to 700 km/h (430 mph) according to Wikipedia) and typically roll down the slopes of a volcano. E.g. here https://www.youtube.com/watch?v=...
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9 votes
1 answer
125 views

The Tambora eruption caused the "Year without a summer". How much would such an eruption today affect the output of solar pv on a global scale?

Are there any estimates for the reduction of global solar insolation at the Earth's surface that a Tambora scale eruption would bring? If our electrical power generation became heavily reliant on ...
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11 votes
1 answer
954 views

Which percentage of $\text{CO}_2$ emissions are human made emissions?

I was watching a science/myth Youtube channel (science mixed with a lot of speculative/fantasy content) with 2M+ followers and the Youtuber said volcano made emissions were higher than human made ...
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3 votes
1 answer
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What kind of lava tube feature is Cleopatra's Grave?

Cleopatra's Grave is a natural feature inside (warning: PDF) Catacombs Cave in Lava Beds National Monument near Modoc, California. Source: LookBeforeYouLive My apologies, as this image is somehow in ...
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