Volcanic Case Studies (1)

Question 1

What causes Strombolian volcanism?

Answer 1

The ascent and bursting of a large gas bubble that we call a gas slug.

Question 2

Which two ways can a gas slug form?

Answer 2

1. Bubbles can coalesce within a conduit. Eventually they grow large enough to form a gas slug.
2. Bubbles can collect at the top of the magma chamber. Eventually the bubbles will enter a conduit as a gas slug,

Question 3

Where is the best example of Strombolian activity?

Answer 3

Stromboli, a small island off the coast of Sicily

Question 4

What is the nickname for Stromboli?

Answer 4

“The Lighthouse of the Mediterranean”

Question 5

What is the population of Stromboli?

Answer 5

500 people

Question 6

How often do Strombolian explosions occur and wherein the Volcano do they occur? (In Stromboli)

Answer 6

Once every 5-10 minutes at the summit

Question 7

How regularly have Strombolian explosions occurred in Stromboli?

Answer 7

Consistently every 5-10 minutes for the last two milennia

Question 8

Why is it important to monitor the Strombolian explosions in Stromboli?

Answer 8

The volcano sometimes produces much larger eruptions which involve hazards such as ash fall, tsunamis and volcanic bombs.

Question 9

What regularly interrupts the quiescent (passive degassing) in Stromboli?

Answer 9

Strombolian explosions

Question 10

Are Strombolian explosions usually hazardous in Stromboli?

Answer 10

Not really, Sometimes they are ashy but they are often ash fre, However sometimes we can see an eruption column, ash fall and pyroclastic density currents.

Question 11

What piece of equipment is used to monitor Stromboli?

Answer 11

UV camera

Question 12

How does the UV camera work?

Answer 12

1. Capture two images of the plume with separate cameras (One at a setting where sulphur dioxide absorbs and one where it doesn’t)
2. Mathematically combine the two images to produce a single image with relative concentrations of sulphur dioxide recorded.
3. Image calibration
4. Produce a graph
5. The values in the original image can be converted to actual sulphur dioxide values.

Question 13

What three things can you do with the values gathered from UV cameras?

Answer 13

1. Estimate the mass of gas slugs
2. Explore links with other signals e.g. seismic
3. Monitor gas flow over time to see if the information can be used to predict a bigger eruption

Question 14

Why are UV cameras so significant?

Answer 14

They are the only way we can measure gas during Strombolian explosions

Question 15

What did computer simulations of gas slug flow show?

Answer 15

That gas mass could be lost from a gas slug

Question 16

How did the UV camera help with computer simulations?

Answer 16

The simulations were only possible due to time resolution of the UV camera

Question 17

What did the measuring of gas at Stromboli help with forecasting?

Answer 17

Discovery of a very large increase in CO2 flux before a major explosive event. Discovered by DOAS and Multi-GAS measurements.

Question 18

What are UV cameras compared with in order to monitor volcanic processes?

Answer 18

Volcanic datasets (e.g. seismic) and computer simulations

Question 19

What type of `volcano is Mt Etna?

Answer 19

Stratovolcano

Question 20

Where is Mt Etna located?

Answer 20

Mainland Sicily (Italy)

Question 21

Which towns are located in the flanks of Mt Etna?

Answer 21

Catania, Nicolosi and Zafferana

Question 22

Which types of activity are seen at Mt Etna?

Answer 22

Passive Degassing, Lava Flows, Strombolian explosions, lava fountains

Question 23

How regularly do Strombolian explosions occur at Mt Etna?

Answer 23

Gas slugs burst every 4-30 seconds

Question 24

How did UV cameras help at Mt Etna?

Answer 24

A pattern was evident amongst the Strombolian explosions. This showed evidence of interacting slugs. This helped with understanding the transition of volcanic activity.

Question 25

What two things have been shown to be linked due to studies at Mt Etna?

Answer 25

Gas Flux and Seismicity

Question 26

Why is studying Mt Etna particularly important?

Answer 26

Perfect for studying activity transitions.

Question 27

What two features of the UV camera make them so important?

Answer 27

Rapid time and spacial resolutions

Question 28

What two other methods of study are combined with evidence from UV cameras in order to unlock more information about the processes within a magma?

Answer 28

Lab experiments and computer simulations

Question 29

How do we use UV cameras to help understand more about a volcanic system?

Answer 29

Compare with other volcanic signals (e.g. seismic)