Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Mount St. Helens wikipedia , lookup
Sidoarjo mud flow wikipedia , lookup
Cascade Volcanoes wikipedia , lookup
Nevado del Ruiz wikipedia , lookup
Cerro Azul (Chile volcano) wikipedia , lookup
Mount Vesuvius wikipedia , lookup
Large igneous province wikipedia , lookup
Volcano (1997 film) wikipedia , lookup
Mount Pelée wikipedia , lookup
Volcanoes and Earthquakes DAY 1 • Objective: –I can explain how a volcano is structured What is a Volcano? • A mountain formed of lava and/or pyroclastic material Anatomy of a Volcano • Vent – Opening in the crust • Crater – Steep-walled depression at the top • Magma Chamber – Where the molten rock waits • Magma Tube – Links the vent to the magma chamber Day 2 • Objective: –I can explain what happens when a volcano erupts Magma verse Lava • Magma – Molten rock under the surface of Earth • Lava – Molten rock on the surface of Earth Factors Affecting Eruption • Magma Composition • Magma Temperature • Amount of Dissolved Gases Viscosity of Magma • Substance’s resistance to flow • Hotter the magma, more fluid and less viscous • Directly related to its silica content – More silica, greater its viscosity (slower movement) Dissolved Gases • Consist of water vapor and carbon dioxide • More gases, the more violent the eruption • Gases –70% water vapor –15% carbon dioxide –5% nitrogen –5% sulfur • Pyroclastic Material – Fragments ejected during eruptions – From very fine to several tons – Ex: • Volcanic Ash • Cinders (lapilli) • Volcanic Bombs Other Eruption Results • Pyroclastic Flow – Consist of hot gases, glowing ash, and large rock fragments – Races down the steep slope • Lahar – Mudflow that occurs when volcanic debris becomes saturated with water and rapidly moves down steep volcanic slopes DAY 3 • Objective – I can describe the locations of volcanoes and the relationship between volcanoes and plate tectonics Plate Tectonics & Volcanoes • Relationship – Plate movement provided the mechanism by which mantle rock melts to generate magma Ring of Fire • Area around the pacific ocean with extreme volcanic activity • This shows the Pacific Plate Boarder Intraplate Activity • Occurs with a plate, not a plate boundary • Hot Spots – Small volcanic region a few hundred kilometers across within a plate – Ex: Hawaiian Islands DAY 4 • Objective: –I can explain what an earthquake is –I can explain why earthquakes happen What is an Earthquake? • Vibration of Earth • Produced by a sudden release of energy • Movement along a fault line Parts of an Earthquake • Focus – Point within Earth where the earthquake starts • Epicenter – Location on the surface directly above the focus • Fault – Associated with earthquakes activity where movement has occurred Causes of Earthquakes • Elastic Rebound Hypothesis – Release of built-up energy – Most earthquakes are produced by the rapid release of elastic energy stored in rock that has been subjected to great forces – When the strength of the rock exceeded, it suddenly breaks, causing the vibrations of an earthquake Foreshock vs. Aftershock • Foreshock – Small earthquakes before the big quake • Aftershock – Smaller earthquakes after the big quake Seismic Science • Seismology – Study of earthquake waves • Seismograph – Instruments that record earthquakes • Seismogram – The record made by a seismograph Day 5 • Objective: –I can explain how to locate origin of an earthquake –I can explain how to measure the strength of an earthquake Earthquake Waves • Two Main Types –Surface Waves –Body Waves • P-waves • S-waves Surface Waves • Seismic waves that travel along Earth’s outer layer • Moves up & down and side to side • Most destructive • Last to arrive at the seismograph Body Waves • P-Waves (primary waves) – They push (compress) and pull (expand) rocks in the direction the wave travels – Can travel through solids, liquids and gases – Fastest waves – First to the seismograph • S-Waves (secondary waves) – Shakes particles at right angles to their travel – Can only travel through solids – 2nd to the seismograph Locating Earthquakes • The difference in velocity of a PWave & S-Wave provides a way to locate the epicenter – Use a travel-time curve graph – Needs at least three seismograph station data Strength of an Earthquake • Two different types of measurements to describe the strength of an earthquake – Intensity – Magnitude Earthquake Intensity • A measure of the amount of earthquake shaking at a given location based on the amount of damage Earthquake Magnitude • A measure of the size of seismic waves or the amount of energy released at the source of an earthquake The Richter Scale • Measures magnitude • Based on the amplitude of the largest seismic wave • A TEN-FOLD system • Largest earthquake record= 9.6 (CHILE) Moment Magnitude Scale • More precise • Amount of displacement that occurs along a fault zone • Most widely used – Estimates energy released by earthquakes Mercalli Intensity Scale • How much damage occurs • Depends on: – Strength – Distance from the epicenter – Nature of the surface material – Building design DAY 6 • Objective: –I can describe the dangers of an Earthquake –I can explain how to make earthquake predictions Earthquake Hazards • Seismic Vibrations – Damage to building depends on several factors • Intensity of vibration • Duration of vibration • What type of material built on • Design of the structure • Liquefaction –Stable soil turns into a liquid that is not able to support building or other structures • Tsunami – Large ocean wave created by an earthquake • Landslides – Greatest damage to structures – Sinking of the ground triggered by the vibration • Fires – Caused by ruptured gas lines Predicting Earthquakes • Short Range – Measure uplift, subsidence and strain in the rocks – Short-range predictions have not been successful • Long Range – Based on the idea that earthquakes are repetitive – Seismic Gap • An area along a fault where there has not been any earthquake activity for a long period of time