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if all the lava is coming out of the earth... where does the earth collapse tofill what came out or is this what causes earthquakes and tremors?

With thousands of tons of lava over hundreds of years, coupled with the oil.coal,iron gas and the general mining that is constantly being taken out of the planet, how long can this go on, before some catastrophe happens, maybe implodes and causes all the hollowness to join up, and maybe collapse????

Valli, have a look at plate tectonics... The planets crust is made of large plates which move over the surface very slowly... new magma is being created as plates slide under each other and are forced back into the mantle, causing them to melt.

Just like to say well done to Dr Field for her clear and precise narrative. Even tho she is my sister and I am proud of her, I would still say the same even if it she wasn't! Makes a change from mumblings.

It's inspiring to read this post and see Dr Field on Volcano Live. As a mature student, I find Dr Field's success to be an inspiration and gives me hope that I can make a change to a scientific career as well.

During the process of subduction oceanic tectonic plates are forced back into the Earth under less dense continental plates. This rock is then melted and the process continues; this is why we tend to find volcanoes along subduction zones, like the Cascades in the United States.

I was particularly interested to learn about Dr Field as I've recently returned to university to study geology. As a mature student it's heartening to learn I'm not too old!

To Lorraine Field : delighted to see your volcano programme. Sorry to have lost touch, We would be pleased to hear from you again. John & Vicki Sargent

Great if you are there in person but generally episode one was boring. Not sure what Kate Humble adds to the programme superficial comments and interviewing. Disappointing after all the hype.

Hi why is it that there are different types of lava? I thought that all magma originated at the mantle which was of a conctant constituence so why in some parts of the world do volcano explode and lava is viscous whereas in others the lava flows reasonably quietly and is fluid

Alison, magma can be derived from a lot of different things. A truly mantle derived magma contains a lot of magnesium and iron-rich minerals, whereas a magma that came from the melting of crustal material will have a whole lot less magnesium and a whole lot more silica (SiO2). This silica content is a big part of why some magmas are runny and some aren't...silica molecules tend to stick together in clumps which makes for a really viscous magma, while the magnesium minerals have less tendency to polymerize and make runny magma. Also, the gas content is a player. Despite how hot it is, all magma contains some amount of water, and it also contains carbon dioxide. While these gases are under pressure, they're in solution and "happy". Once they start to head towards the surface, the pressure drops and they come out of solution and explode towards the surface. If you get lucky and have a low-silica magma (like Hawaii, which is coincidentally also low in gas), you get a gloopy sort of bubble burst, like bubbles popping in mud. If you are unlucky, and have a thick, sticky, high-silica magma with a lot of gas (like Mt. St. Helens) you get a big, violent explosion.

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I appreciate your work, I love the volcano programs, its a real inspirational stuff. Some of the contents are unbelievable. Loved it.
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Hello Lorraine, I was just trolling through the Ö÷²¥´óÐã blogs - then I saw yours and read it. I have to tell you, this is strange. Your life journey might be the total reverse of mine!
I did Geophysics at Durham Uni, and now I am studying Natural Hazards (Masters) at Bristol Uni!!! Thus, the program featured a lot of my lecturers. However, I don't think I want to do it (geology) anymore. I won't be surprise if someone tell me I am going to work in a technology consulting company in 10 years time!
I do like what I learnt at university and still fascinated about the natural sciences.

However, I just don't enjoy researching anymore. You don't really have your hands on things (apart from computers). People tell me it is a shame that I have already determined to put an end to it (Yes, I am still doing my Masters). But I guess if this is not what I thoroughly enjoy, I should not stick with it? I think I ultimately like to help people out with their lives rather than looking at rocks.

Dr Field, I believe you are a very brilliant, experience and wise lady. Would you have a word, a piece of advice for me? Please? As I finish my study very soon and will need to start pathing my future?

p.s. We took the Ö÷²¥´óÐã camera with us to Guatemala fieldtrip as well. But Ö÷²¥´óÐã didn't use our footage at all! It was a great disappointment.
But Volcano Live was brilliant in general.