Volcano Monitoring Quiz

Read the instruction page and work through the recommended web sites before attempting the quiz.

The questions can only be answered by reference to the diagrams and maps in the printed handout provided.

You may attempt the quiz as many times as you like. If there are questions which you get wrong, attempt them again until you understand the problem.

What are the characteristics of short period volcanic earthquakes? (p. 1)

There may be more than one correct answer.
1. They occur during magma intrusion
2. They result from shock waves due to rock fracturing
3. They may be caused by turbulent motion of magma
4. They may be caused by turbulent motion of gas
5. They occur immediately before or during an eruption
What are the characteristics of volcanic tremor? (p. 1)

There may be more than one correct answer.
1. It occurs during magma intrusion
2. It results from shock waves due to rock fracturing
3. It may be caused by turbulent motion of magma
4. It may be caused by turbulent motion of gas
5. It occurs immediately before or during an eruption
Study the graphs relating to basalt lava eruptions of Pu'u O'o crater, Kilauea, Hawaii in 1986 (p. 2, fig. 3). Which of the following statements are true?

There is more than one correct answer.
1. Long period 'quakes build up gradually in intensity before the eruption
2. There is a gradual decrease in long period quakes during and after the eruption
3. There is rapid onset of long period 'quakes immediately before eruptions
4. There is no clear relationship between long period earthquakes and eruptions
5. There is a gradual build-up in short period 'quakes before an eruption
6. There is a sudden onset of short period 'quakes before an eruption
7. There is a gradual decrease in short period 'quakes after an eruption
8. There is a rapid decrease in short period 'quakes after an eruption
9. There is no clear relationship between short period earthquakes and eruptions
What is the interval between the onset of lava eruptions at Pu'u O'o? (p 2, fig 3)

One answer only.
1. 1-7 days
2. 14-20 days
3. 21-28 days
4. 29-35 days
5. 36-43 days
6. 44-50 days
What changes in seismicity occurred at Pinatubo volcano prior to the major explosive eruption of June 15-16 1991? (p. 2, fig. 4). N.B. upper diagrams are maps, lower diagrams are cross sections.

Choose 2 answers.
1. Earthquake hypocentres became deeper
2. Earthquake hypocentres became shallower
3. Earthquake hypocentres migrated towards the volcano's summit
4. Earthquake hypocentres migrated away from the volcano's summit
Examine the ground elevation plot for Krafla volcano, a basalt lava volcano in Iceland (p2, fig. 5). MASL = metres above sea level. What is the cause of the sawtooth pattern?

One answer only.
1. Repeated gradual uplift followed by gradual subsidence
2. Repeated gradual uplift followed by rapid subsidence
3. Repeated rapid uplift followed by rapid subsidence
4. Repeated rapid uplift followed by gradual subsidence
5. None of the above
What caused these changes in ground elevation at Krafla?

There may be more than one correct answer.
1. Uplift due to magma rising to high levels
2. Uplift due to compression of the crust
3. Subsidence due to caldera formation
4. Subsidence due to rifting
To the nearest centimetre, what was the maximum vertical uplift at Kilauea volcano, Hawaii, prior to the August 1971 eruption? (p. 3, fig. 6)

Type your answer in the text area below.
To the nearest kilometre, what was the diameter of the inflated area?

One answer only
Study the diagrams on p 5, and the Campi Flegrei web page.

Now answer the following questions: What is the vertical distance (in metres, to two decimal places) from present sea level to the base of the bored part of the columns at Serapeo, the Roman market:

Type your answer in the text area below.
How much of the vertical height of the columns was bored by marine molluscs? Give your in answer in metres, to two decimal places.
How did ground tilt change before and after the 1989 eruption of Etna? (p. 3, fig. 8).

One answer only
1. Gradual inflation of the volcano before the eruption, followed by rapid deflation afterwards
2. Sudden inflation of the volcano before the eruption, followed by gradual deflation
3. Small inflation and deflation episodes, accompanying an overall inflation before the eruption
4. Small inflation and deflation episodes, accompanying an overall deflation before the eruption
Fig. 7 on p. 3 shows changes in lengths of several different lines between benchmarks on Mt. Etna. Each EDM survey line is several km long. What was the maximum increase in line length during the period 1981 to 1991? Type in a number, to the nearest metre.

Type your answer in the text area below.
Which line showed the smallest length increase from 1981 to 1987? Type the number of the line (for example 10-11) in the box..
Which lines showed negligible length increase during the 1989 eruptions? Select all correct answers.
1. 5-7
2. 8-7
3. 11-10
4. 8-10
5. 8-6
6. 5-8
Page 4 shows various records from Mount St. Helens, leading up to the April 1982 eruption (smaller than the famous May 1980 event). What changes did the volcano show before and after the April 1982 event?

Select all correct answers.
1. Gradual increase in seismic energy release before the eruption
2. Exponential increase in seismic energy release before the eruption
3. Increase in sulfur dioxide before the eruption
4. Decrease in sulfur dioxide before the eruption
5. Steady inflation before the eruption
6. Inflation rate increasing with time before the eruption
7. Rapid deflation after the eruption
8. Continuing inflation after the eruption
On 12 March, how precise was the prediction of when the eruption would occur ('predictive window')? (NB dates are in N American format, so 3/12 is 12 March, NOT 3 December).

One answer only
1. 18 days
2. 20 days
3. 22 days
4. 24 days
What was the predictive window on 15 March?

One answer only.
1. 1 day
2. 3 days
3. 5 days
4. 7 days
5. 9 days
What was the predictive window on 19 March?

One answer only.
1. 1 day
2. 2 days
3. 3 days
4. 4 days
5. 5 days
Which towns and villages on Mt. Etna are most at risk from lava eruptions? (p. 6)

Select four answers.
1. Linguaglossa
2. Milo Fornazzo
3. Catania
4. Paterno
5. Giarre
6. Pedara
What are the main risks to the urban areas around Puget Sound from an eruption of Mount Rainier? See hazards map on the USGS web site.

Choose more than one of the following options.
1. Lava flows
2. Pyroclastic flows
3. Tephra fall
4. Floods
5. Poisonous gases
6. Mudflows
Compare the hazards map for Mount St. Helens (p. 7), constructed before the 1980 eruptions, with the USGS map showing the actual effects of the eruption. Which hazards were successfully predicted?

Choose more than one of the following options.
1. Mudflows into Swift Creek (leads to Swift Reservoir)
2. Debris avalanche into the Toutle River valley
3. Blast effects to the north of the volcano
4. Pyroclastic flows into Spirit Lake
The diagram on p. 8 shows the hypothetical effects of a major caldera-forming eruption (600 times bigger, in terms of volume of material erupted, than the 1980 Mount St. Helens eruption) at the Phlegraean Fields (Campi Flegrei) volcano, Italy, immediately west of Naples. Which of the following local, regional and global effects of such a cataclysmic eruption are predicted by this map?

Choose more than one of the following options.
1. Extensive ash fallout over western Europe
2. Destruction of Rome by pyroclastic flow and fall
3. Ash fallout in Ukraine
4. 15 cm or more of ash fall on Tirane, Albania