Volcanoes – Friend or Foe? What are the effects of volcanoes on man and the environment? Mt St Helen’s Eruption (May 1980) Mt St Helens located on the ‘Ring of Fire’ Mark Mt St Helens on your map of where volcanoes and earthquakes are located. Mt St Helens - Causes of the Eruption Juan de Fuca plate North American Plate Which is the oceanic plate? Task 2: Describe how a volcano is created in 2 sentences. Mt St Helens - The Eruption Video: Mt St Helens • Make notes about the effects of this volcanic eruption on people. Mt St Helens AFTER BEFORE Mt St Helens Consequences of the Eruption N O 10km What damage did the eruption cause? Up to 70mm of ash falls across Washington and East Montana…7000 school students have an early Summer vacation due to problems on the roads Two million birds, animals and fish are killed. Deer mice, chipmunk, vole, gophers, salamander survive the blast. Mudflows block and divert rivers. Hot mudflows raise the temperature of the rivers to 30ºC 60 people die from the eruption. The post office and Lone Fir Motel shut down in Cougar. Damage to crops $175 million More tourism Less tourism Communications threatened – railway and road bridges destroyed, Portland harbour blocked Gophers, through their tunnelling, mix the soil with the ash. This increases the fertility of the soil. Separate the above into the short term and long term impacts of the eruption. Homework: Due:______ • What are the affects of a volcanic eruption on people? Give examples. • Write about 100 words to answer the above question. Homework review: Hot spot volcanoes - Hawaiian Islands Active volcanoes Extinct volcanoes Hot spot In the diagram above, why are the volcanoes to the right of the ‘hot spot’ extinct?