Earth, Brown 2015 (monitoring etc)

5. Monitoring and forecasting volcanic eruptions

What is the purpose of volcanic monitoring?

To detect unrest, issue warnings, and reduce risk.

Why is monitoring and warning systems important?

They protect lives and assets from eruptions.

What is the Value of a Statistical Life (VSL) used for?

Estimating economic benefit of lives saved.

What are major costs of volcanic evacuation?

Direct costs and lost economic activity.

What was the cost of the Guadeloupe evacuation (1976)?

~60% of annual per capita GDP.

How long is typical precursory volcanic activity?

Days to months.

What percentage of stratovolcanoes erupt after 1 month of unrest?

~50%.

What is the role of volcano observatories?

Monitoring, forecasting, and issuing warnings.

How do observatory roles differ globally?

Some collect data only; others issue alerts.

Why are local observatories important?

Volcanoes are localised hazards needing local monitoring.

What is baseline data in volcanology?

Normal behaviour used to detect unrest.

What is instrumental monitoring used for?

Early warning, forecasting, and scientific evidence.

What are key seismic monitoring methods?

Earthquake location, type, and volcanic tremor tracking.

What causes volcanic earthquakes?

Magma movement, rock fracture, or fluid pressure.

What is volcanic tremor?

Continuous seismic signal before eruptions.

What does ground deformation indicate?

Magma movement or pressure changes underground.

What tools measure deformation?

GPS, tiltmeters, InSAR satellites.

What is InSAR limitation?

Not real-time; requires repeat satellite passes.

What do volcanic gases indicate?

Magma ascent and degassing.

Why is gas monitoring difficult?

Atmospheric background CO₂ and H₂O interfere.

What does SO₂ monitoring use?

OMI satellite data.

What is volcanic unrest?

Deviation from normal volcanic behaviour.

How often does unrest lead to eruption?

~47% of cases (2000–2011).

How long does unrest typically last?

Around 500 days on average.

Which volcano type has shortest unrest?

Stratovolcanoes (weeks–1 month).

What % of volcanoes with deformation erupt?

~50% with deformation vs ~6% without.

What is WOVOdat?

Global volcanic monitoring database.

What is the goal of forecasting?

Predict eruption onset and evolution.

What is modern volcanic forecasting based on?

Probabilistic and physical models.

Why are false alarms a problem?

They reduce public trust.

What is a volcano observatory?

An organisation that monitors volcanoes and issues warnings.

How many volcanoes are active in aviation history?

247 volcanoes since 1950s aviation began.

What aviation hazard occurred at Pinatubo (1980s)?

16 ash encounters with aircraft.

What is a VAAC?

Volcanic Ash Advisory Centre for aviation safety.

What % of Holocene volcanoes are monitored?

~14% have some monitoring.

What % of volcanoes are unmonitored?

~25–45% of historically active volcanoes.

What is a minimum seismic network for monitoring?

At least 4 seismometers.

What limits global volcano monitoring?

Cost and resource constraints.

What is GLOVOREMID?

A project improving volcano monitoring in Latin America.

What is satellite Earth Observation used for?

Deformation, gas, thermal and ash tracking.

Why is satellite monitoring useful?

Global coverage of remote volcanoes.

What is the main limitation of satellites?

Not continuous real-time data.

What is key during an eruption in progress?

Ash and hazard tracking for forecasting.

What % of eruptions occur after long repose periods?

~Half of volcanoes have >100-year repose.

What is the main uncertainty in volcanology?

Complex, dynamic system behaviour.