Yellowstone supervolcano

Question 1

Yellowstone overview

Answer 1

• Volcanic activity began around 2 million years ago when giant calder formed
• Two further huge eruptions took place 1.3 million and 640,000 years go
• Because evidence of earlier eruptions has been either buried or destroyed by later ones, it is not known exactly how often the volcano has erupted nor the volume of material extruded
• During largest eruptions, ash was spread over much of the western half of North America, while gases and tiny particles were carried around the globe in the upper atmosphere
• It is likely that this caused a noticeable, though temporary decrease in global temperatures

Question 2

Misconceptions regarding Yellowstone

Answer 2

Yellowstone is overdue a very high-magnitude event - tectonic events do not follow a regular pattern, making accurate and reliable prediction impossible
When Yellowstone erupts it will have severe global consequences - the most probable eruption would be a lava flow or a hydrothermal event, these would have little, if any, impact outside of the Yellowstone region
The Yellowstone magma chamber is growing - no evidence exists for growth in a near-surface chamber of the size required for a super-volcano eruption
Earthquake data indicates magma is moving - recent earthquakes are linked to fractures in brittle rocks, even if long-period events (type of earthquake usually associated with magma movements) are registered, this does not been an eruption is imminent
The caldera surface is rising - measurements have indicated both rises and falls in ground surfaces within the caldera, latest research suggests that volcanoes and display quite rapid ground movements without necessarily erupting

Question 3

Possibility of volcanic activity

Answer 3

• Last erupted around 70,000 years ago
• Given that hotspot under Yellowstone heats, stretches and weakens the crustal rocks, volcanic activity could occur at any time, however the probability of a super-volcano style eruption is exceedingly low