Conservative Boundary Volcanoes Quiz Subduction Continental Crust Conservative Boundary Geosycnline Composite Volcano Shield Volcano Acidic Lava Lahar Pyroclastic Flow

How do volcanoes affect people? The key idea of the lesson is… Volcanoes are hazards resulting from tectonic activity. Their primary and secondary effects are positive as well as negative. Responses change in the aftermath of an eruption. C/S: Different types, cause, primary and secondary effects, positives and negatives, immediate and long-term responses. Monitoring and prediction. By the end of the lesson you will… have two posters, and notes, to explain the advantages and disadvantages of volcanic activity. have notes on how volcanoes can be monitored and predicted

Iceland

Advantages of Iceland’s Volcanic Activity

Eyjafjallajökull, 2010 Composite Volcano Southern Iceland March – October 2010 Series of eruptions (VEI 1-4) Frequent eruptions since last ice age, most small. March eruption – basic lava – effusive April eruption – explosive First warning: earthquakes 2009

Ash 250 million cubic meters of tephra (ash) No flights in 20 countries 10,000 people affected Ash on the ground caused ‘ash mist’

Contributing Factors Volcano under jet stream. Jet stream consistently going south-east. Ice cap melted causing explosive eruption with rapidly cooling lava, so lots of abrasive ash. VEI caused direct ash injection into jet stream.

Immediate Effects and Responses Effusive Eruption 500 farmers evacuated from the local area for 24 hours Flights to and from Reykavik and Keflavik cancelled (20-21 March) Risk map made Roads closed near to volcano (until 29 March) Risk of flash flooding from melting ice (unwarranted) Earthquakes (but largely uninhabited area) 150 m long fissure with basic lava, followed by 200 m fissure

…local companies offered day trips to view eruption. Volcano Tourism …local companies offered day trips to view eruption. Vodafone installed webcams. Icelandic police set up a restricted area, enforced using search and rescue.

Immediate Effects and Responses Explosive Eruption Earthquakes Ash plume 8km high – air travel, tourism, major events, logistics (alternative by road), economic impact (time-sensitive) Melt water from melted glacier caused floods and a lahar Markarfljot river destroyed road 800 people evacuated Unusual lava (high in silica and fluoride) Pollution of streams Farming halted (due to ash) – animals kept inside Airspace closed By 19 April, less ash, lava flow (3 km into the air) Fears of Katla eruption meant tourists left Schools closed, people told to stay inside

Recovery/Long Term Effects and Responses Drop in global CO2 levels because of Iron Area now quiet, with little activity – people returned home Road rebuilt No climatic impact Improved soil fertility in an agricultural region International attention for Iceland – more tourists Possible health risks from ash Fluoride poisoning? Water quality? Talks about air travel in emergencies Studies on effects in Scotland (soil/water) Travel companies collapsed (partially as a result of ash) Nissian distribution and production affected New Zealand boast in exports due to flower and fish demand

Monitoring and Prediction

Task Produce two posters: The Eyjafjallajökull Eruption – background, effects and responses Advantages of Volcanoes – focusing on benefits brought to Iceland (geothermal power/heat, tourism, fertile soils, greenhouses). Once finished: Answer questions 5,6,7 on page 21

Homework Produce a newspaper report on the 2002 Nyiragongo Eruption in Africa. It should be retrospective (looking back on the event from today). Have the following sections: Introduction Short-term Effects Long-term Effects Rescue and Recovery David Johnston

Describe the distribution of the world’s volcanoes (2 marks) Looking at the map below, provide evidence to support the statement that ‘volcanoes usually occur at plate boundaries’ (3 marks) Explain the cause of the Mt. St. Helens eruption (4 marks)