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Help with determining the least dangerous volcanic landform


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1.       If you were to rank volcanic landforms in terms of the risk they pose to humans, which would be the most risky landform to encounter, and which would be relatively safe? Explain your answer.

This is the question in my assignment, I was able to determine the the most dangerous, which are the stratovolcanoes though research, but when I was determining which is the safe one I've encountered a lot of problems. 

Here are the choices base on my textbook - shield volcanoes, cinder cones, calderas, fissures, basalt plateaus, lava domes, and volcanic necks.

Based on what I've searched on the internet, all of the the volcanoes mentioned are dangerous, the calderas are still dangerous due to the active volcanoes that are commonly beneath them like in the case of the yellowstone volcano, fissures are dangerous and can lead to basalt flow or plateaus that an article mentioned to be more dangerous than a super volcano, lava domes can also collapse and create destruction, and lastly volcanic necks can explode due to the buildup of pressure beneath them. At this point I don't even know what's safe anymore.  

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Posted (edited)

I seem to remember you are studying Environmental Science ?

This is heavy geological stuff for that subject.

Certainly explosively eruptive volcanoes offer an immediate candidate, especially the biggest ones.
But these are still single point activities and the level of danger must depend upon where they are located.
Under Tokyo or Mid Pacific ?

Then some eruptions have put so much material into the upper atmosphere that world cooling for several years even to decades have resulted.
Accompanied by noxious gases one of these could affect all humans.

Finally some eruptions, such as the recent one in Iceland, are just large outflows of basaltic material.
But there have been at least two such eruptions in the past that were continent wide in scale.
The Deccan and the Siberian traps.
Another such eruption from Xianging/Mongolia could wipe out most of Asia.

 

Finally here is a good reference book for you

Cambridge University press 2011

erupt.jpg.26c19efc380067a331fb06c9f0b3aa09.jpg

 

I'm very sorry I just re-read the title.

You said the least dangerous. My mistake.

The least dangerous will probably be found at the bottom of the oceans.
I will leave you to investgate further as this is homework help.

Edited by studiot
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Posted (edited)

Thank you sir, you're right I'm actually taking the second semester of my freshmen year. One of our subjects is geology and geography here we kinda tackle in depth how geological processes occur on earth. In my question I was actually asking for the least dangerous among the landforms I mentioned, the most dangerous one, in general are mentioned to be the stratovolcanoes so I kinda relied on that. In terms of what I was looking for,  I can't seem to determine which is the one that will be considered "safe" though I kinda doubt that word after researching a bunch of stuff in the internet. 

Edited by popcornfrenzy
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1 hour ago, popcornfrenzy said:

1.       If you were to rank volcanic landforms in terms of the risk they pose to humans, which would be the most risky landform to encounter, and which would be relatively safe? Explain your answer.

This is the question in my assignment, I was able to determine the the most dangerous, which are the stratovolcanoes though research, but when I was determining which is the safe one I've encountered a lot of problems. 

Here are the choices base on my textbook - shield volcanoes, cinder cones, calderas, fissures, basalt plateaus, lava domes, and volcanic necks.

Based on what I've searched on the internet, all of the the volcanoes mentioned are dangerous, the calderas are still dangerous due to the active volcanoes that are commonly beneath them like in the case of the yellowstone volcano, fissures are dangerous and can lead to basalt flow or plateaus that an article mentioned to be more dangerous than a super volcano, lava domes can also collapse and create destruction, and lastly volcanic necks can explode due to the buildup of pressure beneath them. At this point I don't even know what's safe anymore.  

Domes would be the most dangerous. A dome signifies extremely viscous magma, typically "acid", with lots of silica. Volcanoes with this feature are notorious for eruptions in the form of pyroclastic flows (nuees ardentes). La Montagne Pelee is a classic, as is La Soufriere, currently going off in St Vincent. 

In the terminology I am used to, a volcanic neck is the exposed solidified magma plug (a sort of dyke) left after the erosion of an extinct volcano. So that would be 100% safe. But I admit my terminology may be out of date.

 

 

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2 minutes ago, exchemist said:

Domes would be the most dangerous. A dome signifies extremely viscous magma, typically "acid", with lots of silica. Volcanoes with this feature are notorious for eruptions in the form of pyroclastic flows (nuees ardentes). La Montagne Pelee is a classic, as is La Soufriere, currently going off in St Vincent. 

In the terminology I am used to, a volcanic neck is the exposed solidified magma plug (a sort of dyke) left after the erosion of an extinct volcano. So that would be 100% safe. But I admit my terminology may be out of date.

 

 

Thanks for the answer Sir oh I really thought that it was actually stratovolcanoes that are dangerous since they've taken a lot causalities in the past. For the volcanic neck I found out in wikipedia this passage. 

"When present, a plug can cause an extreme build-up of pressure if rising volatile-charged magma is trapped beneath it, and this can sometimes lead to an explosive eruption." 

Sir umm I just want to further verify which is really the most dangerous and which is the safest, sorry for validating too much. 

 

Sorry for taking some of your valuable time here guys I'm really grateful for the help you are all giving me

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8 minutes ago, popcornfrenzy said:

Thanks for the answer Sir oh I really thought that it was actually stratovolcanoes that are dangerous since they've taken a lot causalities in the past. For the volcanic neck I found out in wikipedia this passage. 

"When present, a plug can cause an extreme build-up of pressure if rising volatile-charged magma is trapped beneath it, and this can sometimes lead to an explosive eruption." 

Sir umm I just want to further verify which is really the most dangerous and which is the safest, sorry for validating too much. 

 

Sorry for taking some of your valuable time here guys I'm really grateful for the help you are all giving me

Yes, I think the term "neck" is used for the extinct eroded form, whereas a plug may be either extinct or just a blockage in an active volcanic conduit, as you say.  

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I still maintain the least dangerous will be found at the bottom of the oceans.

Did you understand this comment ?

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Posted (edited)
10 minutes ago, studiot said:

I still maintain the least dangerous will be found at the bottom of the oceans.

A serious eruption from a volcano at the bottom of the ocean (or a volcano on lonely island in the middle of nowhere), can result in a tsunami on the sea's surface..

https://www.google.com/search?q=underwater+volcanic+eruption+tsunami

 

Edited by Sensei
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Posted (edited)
7 minutes ago, Sensei said:

Serious eruption from volcano at the bottom of the ocean, or volcano on lonely island in the middle of nowhere, can result with tsunami on the sea surface..

https://www.google.com/search?q=underwater+volcanic+eruption+tsunami

 

Good point, +1

However I was not thinking of a single volcano and the question did ask for which landform.

I am also assuming that we are discussing an active volcanic landform.

There is a particular landform that only occur at the bottom of oceans.

Edited by studiot
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@popcornfrenzyThe question you have been set is difficult to answer properly since it contains no timescale.

In the long term, I would rate plateau eruptions as the most potentially dangerous. The Deccan Traps have been mentioned by @studiot . The current preferred view is that the end Cretaceous extinction that killed the non-avian dinosaurs was a consequence of the Chixulub impact and the Deccan eruptions. The Siberian Traps are the prime suspect in the end Permian extinction, the largest of the five major extinctions. Smaller scale such flood basalt eruptions, like the Columbia River Basalts or the Tertiary eruptions in the West of Scotland would have serious global effects and devasting continental ones. In that regard they would compare with the eruption of so-called super volcanoes.

Those I rank as the second most dangerous. A full scale eruption of Yellowstone would effectively end civilisation in North America. On a much smaller scale the 1816 eruption of Tambora, Indonesia caused "the year without a summer" in the northern hemisphere and killed tens of thousands in the resultant famines.

I agree with studiot that submarine eruptions are, with the exceptions noted by @Sensei, the least dangerous. Most volcanic eruptions occur sub-sea, at diverging plate margins. They are deep. They are of low viscosity basalts. They are not large in local scale. They do not show significant variation in scale over time. All these factors combine to make them low risk.

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What do you mean by "volcanic landform".  Much of the states of Washington and Oregon are covered with a layer of basalt from volcanoes.  I certainly would call that a "volcanic landform and it is certainly safe!  Even if the hot spots below it should erupt the lava would not be able get past the basalt.  (Well, there are a coulple of exceptions to that- such as Mount Saint Helens.)

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21 hours ago, studiot said:

Good point, +1

However I was not thinking of a single volcano and the question did ask for which landform.

I am also assuming that we are discussing an active volcanic landform.

There is a particular landform that only occur at the bottom of oceans.

I'm sorry for the misunderstanding I thought the ones you mentioned sir are all dangerous. 

 

17 hours ago, Area54 said:

@popcornfrenzyThe question you have been set is difficult to answer properly since it contains no timescale.

In the long term, I would rate plateau eruptions as the most potentially dangerous. The Deccan Traps have been mentioned by @studiot . The current preferred view is that the end Cretaceous extinction that killed the non-avian dinosaurs was a consequence of the Chixulub impact and the Deccan eruptions. The Siberian Traps are the prime suspect in the end Permian extinction, the largest of the five major extinctions. Smaller scale such flood basalt eruptions, like the Columbia River Basalts or the Tertiary eruptions in the West of Scotland would have serious global effects and devasting continental ones. In that regard they would compare with the eruption of so-called super volcanoes.

Those I rank as the second most dangerous. A full scale eruption of Yellowstone would effectively end civilisation in North America. On a much smaller scale the 1816 eruption of Tambora, Indonesia caused "the year without a summer" in the northern hemisphere and killed tens of thousands in the resultant famines.

I agree with studiot that submarine eruptions are, with the exceptions noted by @Sensei, the least dangerous. Most volcanic eruptions occur sub-sea, at diverging plate margins. They are deep. They are of low viscosity basalts. They are not large in local scale. They do not show significant variation in scale over time. All these factors combine to make them low risk.

I think our instructor is referring to now when he gave us this question because it concerns humanity. Honestly I never thought that this post will blow up but now I think I'll go with what sir @exchemist stated since it was never mentioned in my textbook that volcanic necks are indeed dangerous. 

 

Thank you all for the answers you gave to me I appreciate every information that I get from these replies. 

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41 minutes ago, popcornfrenzy said:

I'm sorry for the misunderstanding I thought the ones you mentioned sir are all dangerous. 

No that is not what I said.

Mentioning the most dangerous (to life ingeneral and humans in particular) was my mistake (although others seem also to have followed suit).
You question was clear enough.

 

However after I realised my mistake I added the part about finding the answer to your question at the bottom of the oceans.

Since this is homework I cannot mention the landform explicitly.

But look at the bottom of the oceans for one of the largest landforms on the planet that has been volcanically active for hundreds of millions of years (and still is), yet poses the least threat to humanity.

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