Volcanoes and Earthquakes By: Hannah Hanania, Madeline Luong, & Cily Simson What is a Volcano? • An opening in the earth’s crust, which allows molten rock, ash and toxic gases to erupt onto the Earth’s surface • Not all volcanoes erupt with the same intensity • Some may release lava, while other volcanoes only let out ash and gases • Volcanoes can be classified as… – Active – Dormant (not currently active) – Extinct (not expected to erupt again) What Causes Volcanoes? • Rock is heated by the extremely high temperatures underneath the Earth’s surface • As it melts MAGMA is formed • The magma becomes less dense and therefore rises to the surface, where it becomes LAVA. The Ring of Fire • Located at the borders of the Pacific Plate and other major tectonic plates •The Ring of Fire contains over 75% of the world's active and dormant volcanoes •This huge ring of volcanic and seismic (earthquake) activity was discovered before the invention of the theory of plate tectonics Effects of Volcanoes… Bad Effects: Good Effects: • Lava, ash fall, and landslides are some of the most dangerous hazards of volcanic eruptions • Give off harmful gases into the atmosphere • Cause acid rain and pollution • Can cause Tsunamis • Create formations and shape the Earth • 80% of Earth’s surface has come from volcanoes • Examples: -Hawaiian Islands were created by five Volcanoes -Rocky Mountains Mt. Saint Helens • Washington State, May 18, 1980 • Blasts started at 220 mph increased to about 670 mph • 57 people died • 185 miles of highways and roads destroyed • Cost $1.5 billion • Thousands of animals killed Fun Facts: • The term volcano, is derived from the name of the Roman God of fire, Vulcan. • Tallest Volcano is Mauna Loa (Kilauea) • Merap, a 9,500 ft high peak on the Indonesian Islandmost dangerous volcano • The Krakatoa volcano erupted on August 26, 1883 and destroyed most of the island of Krakatoa. It is still active now. Earthquakes What is an Earthquake? • A trembling or shaking movement of the Earth's surface • May dramatically change surface of land, and the floor of the ocean • Two main causes of Earthquakes: – Can be linked to explosive volcanic eruptions and are very common in areas of volcanic activity where they occur during or after volcanic eruptions – Can be triggered by Tectonic activity associated with plate boundaries and faults. • The majority of earthquakes world wide are of this type How are Earthquakes Measured? • Measured on the Richter scale • Richter scale was developed in 1935 By Charles F. Richter • Less than 2.0 are called micro earthquakes • Earthquakes greater than 4.5 can be recorded around the world • Richter Scale is based on the intensity of seismic waves which travel through the earth as energy. Effects of an Earthquake • Can cause landslides and floods • Earthquakes that take place under the ocean can sometimes cause tsunamis, or tidal waves. • Can destroy buildings and cities, as well as the lives of many people Recent Earthquakes • Japan earthquake caused a tsunami – 8.9 on the Richter Scale – Over 18,000 people killed – March 11, 2011 • The Haiti Earthquake caused a terrible tsunami - Killing thousands of people and uprooting the lives of millions - January 12, 2010 - 7.0 on the Richter Scale