Questions tagged [volcanology]

The properties and behaviour of volcanoes.

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7
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1answer
221 views

What would 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 ...
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165 views

Is this article self-contradictory, or am I missing something?

This article: Anderson, C. H., C. J. Behrens, G. A. Floyd, and M. R. Vining. 1998. “Crater Firn Caves of Mount St. Helens, Washington.” Journal of Cave and Karst Studies 60: 44–50. discusses, among ...
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357 views

Are Pompeii and Herculaneum unique?

Has anyone ever found or gone looking for similar locations, i.e. volcanic eruption sites in which unfortunate victims – human and non-human – have been entombed in the volcanic ash, with the ...
6
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1answer
960 views

Volcanoes in the Alps and Himalayas and the subduction of Tethys Sea

Geologist have theorized that the Tethys Sea subducted under Eurasian plates. But where are the volcanoes that would have resulted due to this? Where are the volcanoes in the Alps and the Himalayas?
6
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1answer
209 views

What is the mechanism for deep-sea volcanism of the Gakkel Ridge in the Arctic?

Related to an earlier question, What is the geochemical source for the helium detected in deep Arctic explosive eruptions?, where it is stated in the linked article that there is evidence of explosive ...
6
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1answer
578 views

What are the tallest hydrothermal vents in the world?

Hydrothermal vents are commonly found near active volcanic areas and provide for a rich and complex environment for many biological organisms (archaea, bacteria, tube worms...). Many new hydrothermal ...
6
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1answer
419 views

Is the Cameroon Line still an active rift zone?

The Cameroon Line is described by the Oregon State University's Volcano World webpage What is known about the volcanoes of Cameroon? as a a chain of volcanoes extending from Annobon Island in the ...
6
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1answer
74 views

What theories exist connecting volcano temperatures to eruption probabilities?

Wikipedia names thermal monitoring as one of the methods for predicting volcanic eruptions. I was able to find some papers (First, Second) on such thermometry and while they are challenging (I retired ...
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161 views

Basalt vs. columnar basalt

I recently visited a cliff on the south coast of Ulva in the Inner Hebrides where there are ~10m thick flows of columnar basalt. The columnar basalt forming most of the cliff is sandwiched between ...
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2answers
717 views

What would happen if magma flows into a very large oil deposit?

If there were an earthquake that somehow cause a crack in the earth and allowed a significant amount of magma to flow into a very large oil deposit. With that high amount of explosive energy that ...
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528 views

Can we see lava in a divergent tectonic boundary?

Can we actually see an orange line of lava if we look down to the crack of the divergent boundary of tectonic plates?
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688 views

Red volcanic soils - what are the likely constituents?

I live very near an extinct Andesite volcano and hiking in that area I've noticed bands of soil that have a dark red coloration. I've also been in Kauai, one of the volcanic islands of Hawaii, but ...
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63 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 ...
5
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1answer
159 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 ...
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1answer
400 views

Can cooled/hardened lava rock return to a molten state?

Can lava that has cooled to a hardened state be returned to a molten state by, say, a new river of molten lava flowing over it - like re-smelting iron? If you threw a lava rock into the mouth of a ...
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163 views

Yellowstone Eruption Possibility?

What is the probability of the Yellowstone supervolcano erupting during any given year? I had heard that it erupts once every 100,000 years. Does that mean there is a .001% chance of it erupting ...
5
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1answer
29 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?
5
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What drove the Puy de Dôme volcano?

The Puy de Dôme is an extinct volcano located pretty much smack in the middle of France. It last erupted some seven thousand years ago, which in geological terms is fairly recent - prehistoric humans ...
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1answer
111 views

Do higher global temperatures increase volcanic activity and earthquakes?

I've read that when global temperature increases significantly, liquid magma can make it's way closer to the surface of earth, causing increased volcanic activity and earthquakes. Is there scientific ...
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1k views

What is the source of lava of volcano? From magma below crust? Or from molten crust by rubbing?

Ok, it looks like a very simple question but I still have some point want to clarify... Most images explain volcanos contain some orange stuffs as magma below volcanoes as magma chamber, but the ...
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3answers
465 views

Is the term “fertile ash” a misnomer?

I understand that volcanic ash contains minerals and can make soil more fertile. But I've also heard the term "fertile ash" in some documentary (I have forgotten in what context). Is that a ...
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469 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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408 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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Do lava lakes exist in all volcanoes initially?

I know persistent lava lakes are rare, but do they occur in all volcanoes originally, and just not persist over time?
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Difference between the oxygen/$CO_2$ ratio during the period of the dinosaurs and the present

Here's the base of my question: Was volcanic activity more prevalent when the dinosaurs roamed? Is it true that during the time of the dinosaurs, both the oxygen requirements (by all living creatures ...
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1answer
91 views

What is lava called if it has 56% to 64% silica?

We've learnt in science at school that "Mafic" lava forms rocks with 45% to 55% silica, meanwhile "Felsic" lava forms rocks with >=65% silica. So what is lava called in between? Or is it impossible ...
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64 views

Subrelluric forces in a volcanic eruption

I am listening to a song about volcanoes. It is called "Pyroclastic Annihilation" performed by a brutal deth/thrash metal band called "Demolition Hammer". It is from their album "Epidemic of Violence" ...
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1answer
611 views

Are volcanoes formed from earthquakes?

I know that some earthquakes are caused by volcanoes and that some earthquakes can trigger volcanic eruptions close to where the earthquake is. But what if a great earthquake(8.0 or above) occurs and ...
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184 views

Does the size of Earth increase due to volcanism?

In a volcanic eruption, magma rushes to the 'outside' of the Earth. Does this mean the size of Earth also increases? If not, how is the volume left after the magma rushed out refilled?
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Volcanoes in the Great Barrier Reef

Was there ever at any point in time a volcano in the great barrier reef? I thought atolls develop from volcanic islands, and the coral grow around them.
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632 views

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 ...
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1answer
73 views

What causes lava eruptions (and shutoffs)?

I understand the process of volcanism and the reason for magma deposition on the surface of the earth. What is not clear to me, or what seems to be less well explained is why eruptions occur and then ...
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1answer
917 views

The position of magma chambers

Where do magma chambers exist? Is it necessary that they exist in the asthenosphere where the circumstances of temperature and pressure are suitable for the rocks to be molten? Or they exist in places ...
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1answer
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Do the rocks below an active sill go down, or those above go up, or both?

Having read a little about sill formations like the Palisades Sill (eastern USA) and Whin Sill (UK), I understand that strata became separated by the injected layer of magma, with monumental ...
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Can a cryovolcanic eruption be as powerful as a normal volcanic eruption?

The most powerful volcanic eruption in recorded history was the 1815 eruption of Mount Tambora, an explosion equivalent to 33 billion tons of TNT. Is there any way a cryovolcanic eruption could be as ...
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What happens to the earth after volcanism/tectonics slows?

If we move far enough into the future that the core begins to solidify to the point that volcanism and tectonics are non-existent, what does the surface of the planet begin to look like? Does the ...
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246 views

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?
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1k views

Why do human populations concentrate near fault lines, volcanoes, etc.?

I've noticed that many places with large populations tend to be prime zones for natural disaster. Examples: Silicon Valley = earthquakes, Houston = hurricanes and floods, Japan = tsunamis and ...
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1answer
57 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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Why doesn't the whole volcanic cone appear black?

Cooled lava looks black, but why the whole volcano, even near crater, doesn't always appear black like cooled lava?
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1answer
147 views

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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1answer
81 views

Where are these volcanos as seen in this space tweet?

In his recent tweet from the International Space Station as it's current Mission 56 Commander, NASA astronaut Andrew J. Feustel says: This is #Indonesia as viewed from the @Space_Station. With the ...
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1answer
836 views

how high was mount vesuvius (mount somma?) before it erupted in AD 79?

I guess the highest point of the Mount Vesuvius / Mount Somma complex is currently 1,281 metres (4,203 feet). My question is: how tall was it before it erupted in AD 79?
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183 views

If I can drill a hole to mantle, does it form a volcano?

Suppose if I can drill a hole to mantle at arbitrary point of crust, will magma start rise from the hole and finally become a volcano?
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120 views

Do discordants dykes ever travel concordantly (are transgressive dykes a thing)?

Transgressive sills "jump" between bedding planes, following joints: ...
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558 views

Does flow banding only occur in silicic rocks?

I made a video about what I learnt in my A Level Geology course so far, about igneous rocks. One thing I mentioned was that flow banding is mostly only found in silicic rocks (and so mostly rhyolite) ...
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1answer
118 views

How long would it take for Mars to cool after asteroid impact? [closed]

As someone interested in terraforming, the main obstacle to colonizing Mars is the lack of a magnetosphere and Atmosphere. To create a magnetosphere of sufficient magnitude the Martian core must be ...
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1answer
887 views

How vertically deep do lava conduits go?

I'll preface this with the truth and hope it doesn't disqualify the question but rather give context: after reading Journey to the Center of the Earth by Jules Verne, I am amazed at the prospect of ...
3
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1answer
442 views

Would a Yellowstone eruption destroy global agriculture?

Someone recently claimed in my hearing that if the Yellowstone caldera were to erupt, the resulting ash cloud would end all agriculture for a year or two. (The speaker is not a scientist, and neither ...
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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 ...