How the Past Shapes the Present. The Changing Earth - Constructive and Destructive Forces. Model Land Forms. Constructive and Destructive Forces. My ORC Collection > View a Folder. Plate_tectonics. Discovering Plate Boundaries Maps. Downloads All materials created for DPB may be downloaded freely for classroom use. Copyright of all these materials remains with Dale S. Sawyer. Please drop me an email with your comments when you use the materials. Please acknowledge the source when you use the materials in any manner. Maps PDF format requires Adobe Acrobat Reader which can be downloaded free. GIF format will display in your browser. Student Handouts Wrap-up Overhead Transparencies (in PDF format) Set of 16 transparencies in 1 file Individual transparencies. Understanding Plate Motions. Scientists now have a fairly good understanding of how the plates move and how such movements relate to earthquake activity.
Most movement occurs along narrow zones between plates where the results of plate-tectonic forces are most evident. There are four types of plate boundaries: Divergent boundaries -- where new crust is generated as the plates pull away from each other. Convergent boundaries -- where crust is destroyed as one plate dives under another. Transform boundaries -- where crust is neither produced nor destroyed as the plates slide horizontally past each other.
Plate boundary zones -- broad belts in which boundaries are not well defined and the effects of plate interaction are unclear. Illustration of the Main Types of Plate Boundaries [55 k] Divergent boundaries Divergent boundaries occur along spreading centers where plates are moving apart and new crust is created by magma pushing up from the mantle. Mid-Atlantic Ridge [26 k] Lava Fountains, Krafla Volcano [35 k] Types of Boundaries. Crustal Deformation Processes: Folding and Faulting. The topographic map illustrated in Figure 10l-1 suggests that the Earth's surface has been deformed. This deformation is the result of forces that are strong enough to move ocean sediments to an eleveation many thousands meters above sea level. In previous lectures, we have discovered that this displacement of rock can be caused by tectonic plate movement and subduction, volcanic activity, and intrusive igneous activity.
Deformation of rock involves changes in the shape and/or volume of these substances. Changes in shape and volume occur when stress and strain causes rock to buckle and fracture or crumple into folds. A fold can be defined as a bend in rock that is the response to compressional forces. Folds are most visible in rocks that contain layering.
The rock material must have the ability to deform under pressure and heat. A number of different folds have been recognized and classified by geologists. Figure 10l-2: Monocline fold. Figure 10l-7: Recumbent fold. Plate Map. Fault Laboratory. Interactive Fault Map. 1000 km 1000 mi Leaflet | USGS Download Shapefile. Engineering for Earthquakes. Earthquake in a Box. Faults and Earthquakes - DLESE Teaching Boxes. A Model of Three Faults. Grades 7-12 Adapted from the USGS Learning Web Lesson Plans Background One of the most frightening and destructive phenomena of nature is a severe earthquake and its terrible aftereffects. An earthquake is a sudden movement of the Earth, caused by the abrupt release of strain that has accumulated over a long time.
Today we are challenging the assumption that earthquakes must present an uncontrollable and unforecastable hazard to life and property. Materials Objective Students will observe fault movements on a model of the earth's surface. Time Needed 1 or 2 Class periods Materials Needed (per group) Physiographic map of the world Crayons or colored pencils Scissors Tape or glue Metric ruler Construction paper Fault Model Sheet (included) Instructions Have students work in pairs or small groups.
Application Phase Explain that faults are often (but not always) found near plate boundaries and that each type of fault is frequently associated with specific types of plate movements. Extension Part 1. Lesson 4: Plate Motions and Faults | Learn Science at Scitable. Figure 1: Bird's eye view of the Earth's surface 1. Divide your students into three groups (Group 1, 2, and 3). Hand each group one strip of cardboard, one pair of scissors, and colored pencils. 2.
In Group 1, instruct one student to color a road with several houses along it on their piece of the cardboard. This piece represents a bird's eye view of the Earth's surface from above. Next, ask one student to make a vertical line from a point at the center of the cardboard. Figure 2: A cross-section of the Earth In Group 2, instruct one student to color horizontal layers of rocks on their piece of cardboard (you might want to show your students a picture of a mountainside with layers in it).
Figure 3: Cardboard representation of a strike-slip fault 3. Figure 4: Cardboard representation of a normal fault strike-slip faults, based on the relative movement of one side of the fault with respect to the other. Explain to students in Group 2 that they have created a model of a normal fault. 4. 5. 6. Types of Faults Coloring. Faults Study Guide. Modeling Folding and Faulting (Video) Faulting and Folding Animation. Savage Earth: Restless Planet.
Groundshaking is not the only hazard people face during earthquakes. They can also trigger landslides. In 1692, the town of Port Royal, Jamaica, slid into the sea and came to rest 50 feet below the surface. Marine sediment quickly entombed the town, turning it into an undersea Pompeii: In 1959, archaeologists found a pot of turtle soup in one buried home, still sitting in its copper kettle. During quakes, blocks of crust also shift along fault lines, either horizontally or vertically. During the 1906 San Francisco earthquake, the west side of the San Andreas fault slid 21 feet northward. Another hazard is liquefaction. Dynamic Earth . Slip, Slide, & Collide. Faults. Printer-friendly version In the articles you just read, the authors assume you know something about faults: how they are classified, what kind of motion they experience, what sense of stress they feel, and how to recognize them on a map. Therefore, it is time to step back a little and review some basic material about faults and earthquakes.
A fault is formed in the Earth's crust as a brittle response to stress. Generally, the movement of the tectonic plates provides the stress, and rocks at the surface break in response to this. Fault categories The sense of stress determines the type of fault that forms, and we usually categorize that sense of stress in three different ways: compression, tension, and shear. Handily, these three senses of stress also correlate with the three types of plate boundaries.
Compressive stress happens at convergent plate boundaries where two plates move toward each other. Artist's cross section illustrating the main types of plate boundaries. Eliza's nifty sketches. Secrets of the Oracle — History.com Video. Delphic Oracle. Scientific American - Questioning the Delphi Oracle. New evidence of the geological origins of the ancient Delphic oracle (Greece)
Folds, Faults and Mountains. Faults of the Earth. The Earth's Crustal Breaking Point Faulting results when the Earth's crust not only breaks but moves. Stress produces motion in different directions and causes the separate pieces to move in relation to each other. The motion of the crust after breaking is used to classify faults.
In this project, you will study and model the different types of faults and the types of stress that cause them. You will also use models to show the Earth's surface features as a result of faulting. Getting Started Purpose: To determine the distinguishing characteristics of a normal fault. Materials two lemon-size pieces of clay of different colors two round toothpicks table knife Procedure Break each piece of clay in half. Results The clay is cut and shifted so that the layers of colored clay in the two parts no longer form continuous horizontal lines. Why? Each clay color represents a stratum of one kind of rock material. Try New Approaches Compression causes a reverse fault.
This article is brought to you by: Earth Movements. Earth movements Brief description This unit deals with the formation of features on the earth's surface. The forces, which produce physical features, are of two types: internal forces and external forces. Earth movements e.g. folding, faulting, down warping and up warping, volcanicity and earthquakes have formed features on the earth's surface. Earth movements; These are movements which are lateral and vertical, they exert great forces of tension and compression and although they usually take place very slowly they eventually produce very impressive features like the rift valley escarpment in the photograph... Introduction: The forces which produce physical features are of two types i.e. internal forces and external forces.
Internal forces are lateral and vertical forces within the earth surface leading to earthquakes, vulcanicity, faulting and folding. External forces operate on the earth’s surface leading to denudation , glaciation river action and wave action. Brief description: A simple fold. What are the 4 basic classes of faults? Earthquake Faults For background on this animation series, download Background from the Resources box.Animations are available for preview in embedded YouTube. To download, right click the 'Quicktime Animation' link and choose 'Save Target As' (PC) or 'Download Linked File' (Mac).Send us feedback. Dip-Slip Faults Normal Fault In a normal fault, the block above the fault moves down relative to the block below the fault.
This fault motion is caused by tensional forces and results in extension. Quicktime (788 kB) Reverse Faults In a reverse fault, the block above the fault moves up relative to the block below the fault. Quicktime (947 kB) Strike-Slip Fault In a strike-slip fault, the movement of blocks along a fault is horizontal. Quicktime (935 kB) Transform Fault A transform fault is a type of strike-slip fault wherein the relative horizontal slip is accommodating the movement between two ocean ridges or other tectonic boundaries.
Quicktime (4.25 MB) Oblique Fault Quicktime (753 kB) Dr. Animations. Each series of animations below contains text, graphics, animations, and videos to help teach Earth Science fundamentals. Click links or scroll down to view the available animations. Check out our Earth Science Videos pages. Animations Hazards Orphan tsunami How will 3 buildings, engineered equally, on different bedrock react to an earthquake? Plate Tectonics Tectonics & earthquakes of Alaska—More than just plate boundaries NEW! GPS - Understanding Future Earthquakes in the Pacific Northwest Solomon Islands Regional Tectonics Gulf of California tectonics Sumatran Tectonics What is a hotspot? How do Earth's tectonic plates interact? Do subducting plates slide smoothly past one another?
How is stress stored between tectonic plates? Do faults break all at once, or in many short segments? What are the 4 basic classes of faults? What happens when the crust is stretched? GPS -- Measuring Plate Motion Earth Structure Stratigraphy Same earthquake, different stations; why do the seismograms look different? Volcanoes. Foam Fault Activity. GCSE Bitesize: Distribution of Tectonic Activity. 1990 Atlantic Ocean Floor. Geography in the News: New Madrid Earthquake. Earthquake dangers from the New Madrid fault. With the recent earthquakes in Haiti, New Zealand and Japan, Americans may wonder if or when such a disaster will or might happen closer to home.
While most Americans know of the potential for earthquakes along the West Coast’s San Andreas Fault, fewer realize that a major fault line lies near Memphis, Tenn. The New Madrid (MAH dred) fault is one of the most dangerous in the world. Located beneath the upper end of the Mississippi delta, the fault extends from Cairo, Ill., to Marked Tree, Ark., a distance of 130 miles (220 km). Geologists and other scientists have studied the New Madrid for many years. gitn_1090_NGS New Madrid According to the United States Geological Survey (USGS), the New Madrid area experienced a series of earthquakes in 1811 and 1812 that were among the strongest documented in the United States since its settlement by Europeans.
The location of the New Madrid fault creates the potential for very destructive quakes. Undersea Geology. 1. Brainstorm and define underwater landforms. Explain to students that they will be exploring Earth's ocean floor and the types of geologic activity that occur there. Have students imagine what the ocean floor might be like. Ask: What types of landforms are there on the ocean floor? Students may suggest there are mountains, valleys, or flat areas. Explain that geologists and oceanographers often use different terms for ocean floor formations and terrestrial formations. Define on a whiteboard the terms below, creating a key using a different color to represent each term.
A trench is a long, deep depression in the ocean floor. A trough is a gently sloping depression in the ocean floor. An island is a body of land surrounded by water. A ridge is long, narrow elevation of earth. A gap is a steep-sided opening through a mountain ridge. A seamount is an underwater mountain. A rise is an underwater mountain range located where tectonic plates are spreading apart. 2. 3. 4. 5. 6. Rift valley. A rift valley forms where the Earth’s crust, or outermost layer, is spreading or splitting apart. This kind of valley is often narrow, with steep sides and a flat floor.
Rift valleys are also called grabens, which means “ditch” in German. While there is no official distinction between a graben and a rift valley, a graben usually describes a small rift valley. Rift valleys differ from river valleys and glacial valleys because they are created by tectonic activity and not by the process of erosion. Rift valleys are created by plate tectonics. Many rift valleys have been found underwater, along the large ridges that run throughout the ocean. This occurs along the northern crest of the Mid-Atlantic Ridge, where the North American plate and the Eurasian plate are splitting apart.
In the Pacific Ocean, the East Pacific Rise has created rift valleys where the Pacific plate is separating from the North American plate, Riviera plate, Cocos plate, Nazca plate, and Antarctic plate. Great Rift Valley. Seafloor spreading. The San Andreas Fault - Contents. San Andreas Fault May Be Rare Quake "Superhighway" Southern California Long Overdue for Quake, Experts Say. Next Great Quake: Drilling the San Andreas Fault for Answers. A New Hawaiian Island. Hawaii Geology. Ring of Fire. 14 dead as Indonesian volcano erupts. What Causes an Earthquake? Faults Explained. Earthquakes 101. Virtual Lab - Earthquake Epicenters and Volcanoes. IRIS Earthquake Browser. WebQuest Projects - Earthquakes and Tsunamis. John Muir Owens Valley California Earthquake - 1872. WebQuest Projects - Mountain Building.
Mapping the Shape of Everest. Shaping the Tallest Peak on Earth. ADDITIONAL READINGS. Hayward Fault Article, Earthquake Science Information, Earthquake Faults Facts. China earthquake points to future risk sites. Why Was the Virginia Earthquake Felt So Widely? Haiti Earthquake Disaster Little Surprise to Some Seismologists. Using ocean waves to predict the power of earthquakes. Faults" Denali Fault. Japan's 2011 Earthquake Happened In An Area Considered Low-Risk. Where's Next? Volcanism_Lessons. Iceland volcano: and you thought the last eruption was bad... Studying Seafloor Spreading on Land. Iceland Offers Rare Glimpse of Tectonic Meeting Place ? Mid-Ocean Ridges. Japan's Newest Island Is Now Eight Times Bigger. BBC Earth - Mid-ocean ridges create new sections of tectonic plates. A seismic shift in Ohio’s concerns over earthquakes. Earthquakes and Seismic Risk in Ohio. Ohio Epicenters.