Mt.Etna, Sicily: the lava hazard…

Mount Etna 1993: Diversion channel being dug adjacent to the main lava flow in an attempt to divert it ..

Diverting Lava Flows (‘Modifying the Event’- reducing the risk of damage ) Explosions: Some success on Mt. Etna, Sicily in 1983. 30% of lava flow was diverted from its course. Explosives were used to remove part of the lava wall so that the lava flowed into a diversionary canal which was dug adjacent to the main flow. As a result of this volcano management the villages of Rocca and Ragalna were saved.

3. THE ROLE OF GIS MAPPING IN HAZARD MANAGEMENT ( ‘Modifying the risk’) Ocean-wide, 2004 NOAA

WHITEBOARD PAIRED THINKING In what ways can technology aid disaster management ? 3 mins

The role of GIS in disaster management ‘GIS can be used in all stages of the disaster management cycle.’ Technology can be used to: Predict – warn for evacuation, help insurance companies assess risk, prioritise spending, help decision-makers carry out cost-benefit analyses of defences Assist in emergency management – reconnaissance, mapping, weather forecasts, damage assessment, Identify assets – those at risk, and those that can be used for support (eg sports stadia, schools, cemeteries/morgues) Mitigation – map areas of greatest vulnerability; produce zoning policies

GIS: Tsunami time travel map as tsunami wave spreads across the Pacific Ocean

4. Hazard resistant design and engineering defences ( ‘Modifying the event’- reducing the damage p.73) Collapsing buildings are one of the main causes of death and damage from tectonic hazards so designing buildings that can withstand hazard events more effectively is key to protecting lives and property. (See more notes booklet p.80)

Which shape of building would be most ‘earthquake proof’?

ASEISMIC (Earthquake proof ) STRUCTURES: This is San Francisco in the USA. Why does this skyscraper have a wide base? For stability….

Torre Mayor, Mexico-225m (S.USA’s tallest earthquake proof building)

Hazard resistant design in volcanically risky areas: Building structure design can do little to resist lava, pyroclastic flows and lahars but they CAN be protected against ash, which has the largest spatial impact. Roofs have to be strong and steeply pitched so they shed and dispel as much ash as possible ( see next slide- Japan) In Hawaii, timber houses allow residents in high risk areas to dismantle and move houses if necessary.

An example of urban design used to mitigate the effects of ash fall from a volcano in Kagoshima, Japan. The design of the housing includes gutter-free roofs. 

Mitigating earthquake effects: Safe Houses in the Developing world? The earthquake in Haiti was a reminder: Billions of people live in houses that can't stand shaking. Yet safer ones can be built cheaply—using straw, adobe, old tires—by applying a few general principles…. Let’s look at a few examples of housing methods in 4 of the most seismically hazardous and economically least developed places on earth….

http://ngm.nationalgeographic.com/big-idea/10/earthquakes-pg2

http://ngm.nationalgeographic.com/big-idea/10/earthquakes

Pakistan: Solution? Light walls and gables Lighter buildings subject to smaller forces Compressed straw bales held together with nylon netting Within plaster sandwich

Haiti: Solution?: Small windows ,light roofs.. Concrete roofs collapsed on many homes killing many. Metal roofs and wooden trusses are lighter and more resilient Smaller, regularly spaced ‘window’ openings cause fewer stresses In Haiti disaster improperly re-enforced walls collapsed along with heavy roofs

Peru: Reinforced Walls Eucalyptus and Bamboo structures help to strengthen Plastic meshes are effective too Need not be a metal mesh

Indonesia: Confined Masonry Brick wall framed within concrete uprights – corner column And fixed horizontal beams – crowns The ‘box’ flexes on cheap ground absorbers made from tyres

5. Chilling lava flows by spraying seawater (‘Modifying the event’- ADD TO P.73 and/ or notes blank pages..) It may be possible to modify the volcanic event once the eruption has started but only really lava flows… Water sprays: e.g. successfully used to cool lava flows during the 1973 eruption of Eldfell on Heimaey island, Iceland. 70 farms and homes were buried beneath tephra and 300 were burned by fires and or lava flows that were heading for the harbour ( the economic lifeline of the island). Seawater was sprayed onto the lava to slow down movement by chilling it.30 km of pumps were used and 43 pumps of water pumped 6 million cubic metres of water at a rate of 1m/sec3. The effort saved the port and the residents returned to rebuild their town.

https://www.youtube.com/watch?v=ghl33n26d44&t=1s

Using water sprays on Heimaey Island eruption 1973

HAZARD ADAPTATION STRATEGIES ( ‘Modifying the vulnerability/risk’) 1. High tech monitoring