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Types of volcanic eruptions (AQA A level geog, old spec help)

Hi,

Hope everyone's having a good christmas!

My geography teacher is rubbish, so i've been spending lots of my time putting together notes on tectonics. However, i'm a bit stuck. The spec says 'Variations in the type and frequency of volcanic activity in relation to types of plate margin and types of lava'.

I'm assuming this means just get information about the different types of eruptions e.g. Plinian and Strombolian etc. I've been compiling most of my notes from the text book and revision guide, but they don't seem to mention anything about this part of the spec.

So, I have two questions:
1) Is this what it means? Is there anything else i need to research? What about the different eruptions do i need to know?
2)Does anyone know any good websites or have any good notes on this stuff, because we barely covered it in class and i have zero notes on it. I've looked it up, but it's a bit confusing.

Thank youu!!

Reply 1

aamirac

Original post by Laurenloops

Ahhh I'm going to presume that you're doing A2 AQA Geography right?
I believe it comes under ''major extrusive landforms''. I have a document (see attached) that has most of the information, if there's anything you don't understand feel free to ask.(since they're just my revision notes hahaha) :h:

Vulcanicity.docx477.0KB

Reply 2

username2088165

Hey Laurenloops,

I did A Level Geography with WJEC, so I used a different specification however we also covered plate tectonics, volcanoes etc.

My guess would be that you need to learn the types and frequencies of eruption in terms of whether they are explosive (produce large eruptions with high amounts of pyroclastic material and ash), or effusive (produce smaller eruptions with high amounts of runny lava and little pyroclastic material), and how often they occur (i.e. explosive eruptions occur relatively infrequently, whereas effusive eruptions may occur regularly or even continuously).

Different styles of eruption occur at different plate margins, with explosive eruptions generally occurring at destructive/convergent plate margins, and effusive eruptions at constructive/divergent margins and hot spots. The type of lava may also refer to whether the lava is considered silicic/felsic or intermediate (these lavas, e.g. andesite, contain high amounts of silica and are viscous, producing explosive eruptions), or mafic (these lavas, e.g. basalt, are low in silica and have very low viscosities, and lead to effusive eruptions).

I just thought I'd give you my opinion on what the spec might be talking about (although it looks like aamirac will be able to help you better as as she's actually with AQA!) :smile:

Reply 3

Laurenloops

Thank you sooo much both of you, that's really helpful!! Yes, I am doing A2 AQA geog :smile:

I just found this mark scheme answer that seems like it relates to this as well, it has details about type of volcanic activity, frequnecy of volcanic activity, type of plate margin and type of lava all in relation to one another. I'll link it below:

http://www.geog.biz/wp-content/uploads/2014/04/AQA-GEOG3-W-MS-JUN11.pdf

The question was 'In what ways does volcanic activity vary in relation to the type of plate margin along which it occurs', and on the mark scheme document it is question 3 (Has a table of things).

So, if i learn that and the stuff on aamiric's notes, is that everything covered?

Thank you again :biggrin:

Reply 4

MapleMaypole

Original post by Laurenloops

I'm doing AQA Geog the old spec too.

We did a table on Constructive Plate Margins and Destructive Plate Margins. Then described the movement, type of magma, lava characteristics, types of eruption, material erupted, frequency of eruption time, types of volcano characteristics and an example.

If you want I can send you a picture of the table?

And I've also added the VEI and types of lava for them!! :smile:

Hope this helps

Reply 5

Laurenloops

Original post by MapleMaypole

Hope this helps

If you could send a pic, that would be amazing!! I wish my teacher did that with us, it sounds so helpful!

Reply 6

MapleMaypole

It's kind of messy and not very detailed but I'll write a small paragraph on each:

Constructive Margins:
This is where two plates move apart and magma rises and cools at the surface. The magma type is Basaltic (the most alkaline) and is fast flowing with a low viscosity. This is common for volcanoes with the VEI 1 to 4 (Icelandic, Hawaiian, Strombolian, Vulcanian) and also for Fissure Eruptions, Shield and Composite volcanoes. The eruptions are gentle with little violence and they produce mainly lava. The eruptions are frequent and can be continuous.
Eg - The Mid-Atlantic Ridge or East-African Rift.

Destructive Margins:
Plates move towards each other and one plate is subducted, or a fold mountain/collision margin can form. The magma p
roduced is high in viscosity and is Rhyolitic (Acidic lava). This is common for Volcanoes with the VEI of around 6-8 and Dome/Acid Volcanoes. The eruptions are explosive and contain lava, gases, ash, lava bombs etc. The eruptions aren't too frequent and they have periods of dormancy.
Eg - Yellowstone

Also, along the VEI magma type becomes more viscous:
1-4 = Basaltic
4-6 = Andesitic
6-8 = Rhyolitic

I'm not sure how useful this is :tongue: