Transcript Volcanoes
Volcanoes The Earth’s land builders. What is a volcano? • The land around an opening in Earth’s crust where molten rock exits the earth. Is all lava the same? • Pahoehoe • Aa • Pillow Lava Do all volcanoes erupt violently? • No. All volcanoes are different. Some erupt violently due to trapped gasses. Some flow gently due to a low viscosity. What kinds of volcanoes are there? • • • • • Composite Shield Cinder Cone Caldera Lava Plateau Composite Mt Shasta Shield Mauna Loa Cinder Cone Wizard Island Caldera Crater Lake Lava Plateau Columbia Plateau Where are volcanoes found? • Plate Boundaries • Hot Spots What is the biggest volcano? • Depends on what biggest means. – Diameter – Height above sea level – Height above base – Highest volcano- Ojos del Salado – World’s largest- Mauna Loa – Solar System- Olympus Mons • http://www.skimountaineer.com/ROF/VolcanicSeven.html What comes out of volcanoes? • Lava • Pyroclastic material – – – – Ash Lapilli Blocks Bombs • Gas – – – – – Water vapor Sulfur dioxide Carbon dioxide and carbon monoxide Hydrogen Hydrogen sulfide and others Gases • Gases can be released even when a volcano is not erupting • Vents that expel gas from a volcano are called fumaroles. How do volcanoes affect the Earth? • • • • Land formation and mountain building Expelled water adds to our hydrosphere Expelled gases change our atmosphere Expelled gases and particulates can change our weather • Eruptions can destroy towns/cities • Toxic gases can smother living things Do volcanoes affect our weather/climate? • Yes. Volcanic ash is reflective and can cool the earth locally. This effect may last days to months. • Volcanic gases such as sulfur dioxide SO2 convert to sulfuric acid H2SO4 in the atmosphere • Sulfuric acid aerosols (tiny droplets) remain in the atmosphere for months to years. Can we predict eruptions? • • • • Somewhat. Scientists monitor volcanoes Seismic activity Sulfur dioxide gas Ground deformation such as swelling or bulges • Evacuation plans are in place in high risk areas What other planets/moons have volcanoes? • Mars- Old inactive volcanoes – Olympus Mons over 16 miles high • Our Moon- Old inactive volcanoes • Venus- Some may still be active • Io- Moon of Jupiter • http://geology.com/articles/active-volcanoes-solar-system.shtml