1. Management of volcanoes
Management strategies generally fall into 3 categories:
Prediction
Protection / Mitigation
Preparation / Adaptation
The 3 Ps

2. Prediction
Identify where a volcano is located is easy. Knowing exactly when it will erupt and the way it will erupt isn’t.

3. Prediction worked in the Philippines
Aggressive monitoring and public information campaigns did their job according to the director of PHIVOLCS.
A big part of the success in this instance was due to timing – there was a steady escalation and build up which gave people enough time to react (this isn’t always the case) – if the eruption is very drawn out people will become impatient and then less likely to listen to final warnings.
20 years on, monitoring of the volcano is much more simple due to technological advances- the internet allow scientists in the Philippines to consult scientists in the US, GPS and radar satellites make it possible to measure changes in the ground.

4. Protection / Mitigation
Involves action to reduce the severity of the eruption

5. Building design to prevent damage
After studying building affected by ash after the Pinatubo eruption it was found that:
Wet ash remained on roofs with up to a 25° pitch
Buildings tended to suffer worse damage if they had a roof span of over 5 metres
Wooden framed building were affected worse than concrete structures
New buildings have therefore been designed with narrower span roofs with steep pitches using materials such as metal for the roof as this will allow ash to shed more easily
In Mt Sakurajima in Japan, 10,000 people live around this popular tourist island.
Volcano shelters have been built that will withstand a direct hit from a 50kg volcanic bomb

6. Eldfel volcano – Heimaey (Iceland) 1973
In Jan 1973 the volcano erupted, after the inhabitants of the island were evacuated the authorities turned their attention to protecting the houses and the harbour (essential to the economy of the island).
Firefighters used sea water to spray the front of the lava flow - 32 pumps (each spraying up to 1000 litres per second) were used which after 3 months saved 2/3 of buildings in the main town and stopped the lava 100 metres from the harbour entrance.
In some causes, protection is possible but is very reliant on the nature of the eruption.

7. Lahar protection in the Philippines
For the protection and rehabilitation of lahar-threatened areas in Central Luzon, a 24-kilometer “Megadike”was constructed in 4 months to protect Bacolor. The megadike served as a defence of the vulnerable areas against rampaging lahars during the 1996 rainy season.
Mt Pinatubo

8. Lahar warning systems
USGS scientist installing a lahar warning system on the flanks of Mt Pinatubo - Radiotelemetered rain gauges provide data on rainfall in lahar source regions, acoustic flow monitors on stream banks detect ground vibration as lahars pass, and manned watchpoints further confirm that lahars are rushing down Pinatubo’s slopes. This system has enabled warnings to be sounded for most but not all major lahars at Pinatubo, saving hundreds of lives.
Warnings are announced over the radio, through local authorities, or, in symbolic form, through the sound of gunshots and the pealing of church bells.
This warning sign is from New Zealand.

9. AVOID system
AVOID  is an awareness device for providing real-time imagery of volcanic ash ahead of a jet aircraft. Information is supplied to the cockpit from two fast-sampling, imaging infrared cameras that are tuned to detect hazardous volcanic ash particles in the airspace up to 100 km ahead of the aircraft day or night. At normal flight cruising altitudes and speeds this will give a pilot-7 – 10 minutes warning of a potential dangerous encounter with an ash cloud.
AVOID consists of two infrared cameras, each filtered to a specific wavelength channel.  By measuring the differences in radiation received at each wavelength, the AVOID software is able to convert the signal into ash concentration.  When coupled with GPS and airspeed data, “ash dosages” can be quickly determined and displayed in real-time.

10. Hazard mapping
Mount Rainer in the Cascade mountains in Washington State is one of the most closely monitored and studied volcanoes in the world. One reason for this is that there are 3.5 million people living in close proximity to the volcano.
Geological studies of the nature and extent of deposits from past eruptions, lahars and floods provide evidence for hazard assessment.
Following this, hazard maps have been produced identifying areas of greatest risk. This then informs land use planning policies to avoid building in the high risk areas.

11. Preparation / adaptation
Involves preparing the public and emergency services for volcanic eruptions and trying to change or adapt behaviour in order to reduce the severity of an eruption.

12. Public preparedness
In Japan, volcanic activity is rated with five levels; 1 (calm), 2 (slight activity), 3 (small to medium activity), 4 (large activity) and 5 (catastrophic activity). 
The public are made aware of the risks through radio broadcasts, newspapers, television and education campaigns. These include evacuation routes, do’s and don’ts, how to access the information helpline and relevant authorities. The information also assures the public that the authorities are in control.
Around Mt Sakurajimain Japan, the government holds annual disaster drills for emergency services and to raise awareness and school children have to wear hard hats as part of their school uniform due to the frequent risk of volcanic debris

13. Public preparedness

14. Prediction

15. Protection / Mitigation

16. Preparation

17. More reading…

18. To what extent can prediction, protection and preparation mitigate volcanic hazards?