You've been sending us questions all week. Here are answers to some of the most commmon.

It's true.  Most volcanoes do occur at plate boundaries.  However, they can also occur at what are known as hotspots - places where stationary plumes of magma rise from deep within the Earth's surface.

EXPLORE: What are hotspots, and which volcanoes lie above them?

When Iain mentioned that Mauna Loa in Hawaii was the second largest volcano in the Solar System, lots of you asked what the largest was.  The answer is Olympus Mons on Mars.

EXPLORE: Olympus Mons

EXPLORE: Jupiter's moon Io is the most volcanic body in the Solar System



Yes. The hill of Arthur’s Seat in Edinburgh is all that remains of a volcano that last erupted some 340 million years ago. Volcano Live's Ed Byrne listed it as his favourite volcanic feature in the UK.

DOWNLOAD: A guide to volcanic walks in the UK (PDF - 3.4MB)

A dormant volcano is one that is not currently erupting, but could erupt again one day.  An extinct volcano is one that scientists think will not erupt again.

Our resident volcano expert Dr Clive Oppenheimer answered this in our web chat on Monday night.  According to Clive, volcanoes emit a tiny fraction of greenhouses gases compared with human activity.  However, large eruptions can cool the planet for a couple of years.


WATCH: Iain Stewart on the year without a summer

REPLAY: Web chat with Dr Clive Oppenheimer

You can.  It's estimated that there are thirty thousand volcanoes under the sea.  Measured from the sea bed, many are taller than Everest.

WATCH: David Attenborough explores how underwater volcanoes can be thriving ecosystems

The last volcanic eruption in the UK was around 55 million years ago.  55 million years is many times longer than humans have been on the planet.

Iain Stewart describes Britain's volcanic past

This was one of the most common questions we received this week.  The reason is that hot objects give off energy in the form of light.  Orange lava is hotter than red.

Iain Stewart answers on Volcano Live

WATCH: Dr Yan from Bang Goes the Theory explains why hot objects glow

According to the United States Geological Survey, the deadliest eruption in recent history was Krakatoa in 1883.  The major cause of destruction was not lava or pyroclastic flows, but the enormous tsunami which resulted from the eruption.

More about Krakatoa

However, eruptions in the past may have had planet-wide consequences.

WATCH: BBC Horizon asks whether volcanoes could have caused mass extintions

More from your favourite BBC experts