Environmental Effects of Volcanic Eruption

Environmental Effects of Volcanic Eruption Environmental Science Frankie Bowman 2023 Name: ____________________________________________________ Period: _____ Date: __________ Essential Question: How is the environment affected by volcanic eruption? The sudden violence of volcanic eruptions causes catastrophe and devastation. Various notorious eruptions of volcanoes in the past, such as Mount Pelée, Tambora, Krakatau and Pinatubo have demonstrated the devastating impact of volcanic activity on nearby landscapes and communities. These are some of the environmental effects of volcanic eruptions. 1. Pyroclastic flows are mixtures of hot gas, ash and other volcanic rocks travelling very quickly down the slopes of volcanoes. Pyroclastic flows are so hot and choking that if one is caught in one the person will certainly be killed. Because these flows are very fast they cannot be out-runned. If a volcano that is known for producing pyroclastic flows is looking like it may erupt soon, the best thing is to evacuate all the people living near the volcano. 2. Volcanic ash is a volcanic rock which is exploded from a vent in fragments less than 2mm in size. Volcanic ash-particles are like small sharp glass-particles that damage anything they come across. During heavy ash-rains houses and buildings may collapse, people and animals may die by lack of oxygen. Ash clouds causes big problems for aviation. Airplanes can crash when ash clouds choke their engines. Ash cloud can also block sunlight and cause global cooling. 3. Volcanic Gases: Mount Pinatubo's (Philippines) devastating explosion on June 15, 1991 resulted in an incredible surge of sulfur dioxide gas into the stratosphere where it combined with water to form acid rain (sulfuric acid). The new aerosol deteriorated the Earth's ozone layer by altering the chlorine and nitrogen compounds. Carbon dioxide was also released that elevated global warming and also contributed to acid rain. 4. Lahars: However, of all the effects of volcanoes, mudflows or lahars are the deadliest. Debris flows of mud, rock, and water travel down the flank and into valleys and streams at velocities of 20 mph to 40 mph. Some of the most extreme cases have lahars with a consistency of wet concrete flowing up to 50 miles. They destroy houses, trees, and huge boulders like a flood 5. Debris avalanches and landslides can produce numerous dangers. The mixture of debris from a landslide or avalanche with water may produce harmful lahars. They also can dam rivers or cause flooding. Perhaps one of the most important hazards that can be produced by volcanic eruption caused earthquakes, avalanches or landslides is a tsunami. Tsunamis are large sea waves that have long wave periods. When these waves reach coastal areas, they can go far inland which can cause a lot of damage. 6. Volcanic blast occurs when magma rises asymmetrically into the cone, making one sector of the volcano bulge outwards and become unstable. At Mount St.Helen’s eruption, the volcanic blast very hot (200C) blast devastated an area of 600sqkm! Trees and buildings were razed to the ground and scorched. 7. Lava flows burn or bury everything they come across. They can run over houses, roads, and any other structures. The speed, and the power of the lavaflow depends on the type of lava. Aa lavas for example can leave the vent with a speed of about 50km. The surface the lava flows on will be changed by very quickly emplacing a layer of very new and hot rock onto the pre-existing terrain. The pre-existing terrain is destroyed by the lava flow. People rarely get killed directly by lava. However, lava flows may start fires which are a lot more dangerous for the environment around the volcano. Clarifying Objectives: 1. Give four examples of volcanoes that erupted with devastating effects. Mount Vesuvius in AD 79, Krakatoa (Krakatau) in 1883, Mount St. Helens in 1980, Mount Pinatubo in 1991 _____________________________________________________________________________________ 2. What is a pyroclastic flow? It is a fast-moving current of hot gas and volcanic matter that flows downhill from a volcano during an eruption. _____________________________________________________________________________________ 3. What is the best thing to do when a volcano is about to erupt? Follow evacuation orders issued by authorities and move to a safe location away from the volcano. _____________________________________________________________________________________ 4. What is a volcanic ash? Volcanic ash is tiny rock and mineral particles ejected during a volcanic eruption. _____________________________________________________________________________________ 5. Why do houses and building collapse because of volcanic ash? Think! Volcanic ash can accumulate on roofs, causing them to collapse under the weight, and also because ash can mix with rainwater, creating a heavy sludge that weakens structures. _____________________________________________________________________________________ 6. Why do they cancel flights when there is a volcanic eruption nearby? Think! Volcanic ash to damage aircraft engines, posing a significant safety risk. _____________________________________________________________________________________ 7. How can ash clouds cause the lowering of Earth temperature? Think! This is caused by reflecting sunlight back into space, reducing the amount of solar radiation reaching the Earth's surface. _____________________________________________________________________________________ 7. What are the gases did Mt. Pinatubo release in the stratosphere when it erupted in 1991? Mt. Pinatubo released sulfur dioxide (SO2), carbon dioxide (CO2), and water vapor (H2O) into the stratosphere during its 1991 eruption. _____________________________________________________________________________________ 8. What are the effects of sulfur dioxide and carbon dioxide to the environment? _____________________________________________________________________________________ Sulfur dioxide contributes to acid rain and air pollution, while carbon dioxide contributes to global warming and climate change. _____________________________________________________________________________________ 9. What is considered as the deadliest among the effects of volcanic eruption? Why? The deadliest effect of volcanic eruptions is usually the pyroclastic flows, as they are extremely fast-moving and can _____________________________________________________________________________________ destroy everything in their path with high temperatures and suffocating gases. _____________________________________________________________________________________ 10. What is Lahar? It is a type of mudflow or debris flow composed of volcanic ash, rock fragments, and water that flows down from a volcano's slopes during or after an eruption. _____________________________________________________________________________________ 11. How are tsunamis formed? They are formed by the displacement of water, often by undersea earthquakes, volcanic eruptions, or landslides. _____________________________________________________________________________________ 12. What is a volcanic blast? It is a violent explosion of magma, gas, and ash from a volcano's vent, often occurring during the initial stages of an eruption. _____________________________________________________________________________________ 13. How is lava dangerous? Lava is dangerous because it can flow quickly and burn everything in its path, including buildings, vegetation, and people. _____________________________________________________________________________________ 14. What are the seven effects of volcanic eruption? The seven effects of volcanic eruption are: pyroclastic flows, lahars, volcanic ash fall, lava flows, volcanic gases, __________________________________________________________________________________ ___ tsunamis (if the volcano is near water), and long-term environmental impacts such as climate change. _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ Matching Type: Write the letter of your answer on the space before the number. C _____ 15. Lahar K _____ 16.Pyroclastic flow E _____ 17. Volcanic ash F _____ 18. Volcanic gases G _____ 19. Global cooling B _____ 20. Tsunami H _____ 21. Lava D _____ 22. Pacific Ring of Fire I _____23. Volcano J _____ 24. Earthquake A _____25. Acid rain A. sulfur dioxide gas combined with water. B. Giant waves caused by earthquakes. C. mudflows from volcanic slopes. D. volcanoes lining the edges of the Pacific Ocean. E. volcanic particles that cause problem with aviation. F. sulfur dioxide and carbon dioxide. G. dust scatters in the atmosphere and covers the Sun. H. molten rock. I. Earth’s vent. J. sudden movement of earth crust. K. mixtures of hot gas, ash, and rocks rapidly flowing along the slope of the volcano.