Lesson 3 Analyzing Earthquake Data Notes PDF

Lesson 3 Analyzing Earthquake Data NOTES A wave originates at one point and radiates outward in all directions. Earthquakes produce ground motions that can be detected and recorded by scientific instruments. Earthquakes release energy that travels in waves and can cause damage to structures....

Lesson 3 Analyzing Earthquake Data NOTES A wave originates at one point and radiates outward in all directions. Earthquakes produce ground motions that can be detected and recorded by scientific instruments. Earthquakes release energy that travels in waves and can cause damage to structures. Body waves (P- and S-waves), which travel at different speeds, can be modeled using a stretched spring. Surface waves form after body waves reach the surface and cause damage to man-made structures. Ground motion resulting from an earthquake can be detected and recorded with a seismograph; a seismogram is the recording made by a seismograph. Seismograms are used for data analysis and interpretation. Different earthquake waves travel at different speeds and therefore arrive at seismic stations at different times. The focus of an earthquake is the place under Earth’s surface where the quake’s energy is released, while the epicenter is the point on Earth’s surface directly above the focus. Earthquake epicenters are located by triangulating data from three seismic stations. Earthquakes are natural events that produce destructive waves that carry energy across Earth’s surface. The properties of earthquakes are related to the damage they can produce. Analysis and interpretation of the data can reveal the properties and characteristics of an earthquake..An aftershock is a later earthquake that occurs before an area has returned to its normal level of seismic activity. Like all earthquakes, aftershocks can damage structures. According to the United States Geological Survey, “There is no scientifically plausible way of predicting the occurrence of a particular earthquake.” Earth has layers, including a crust, a mantle, and a core. Although it is not possible to predict earthquakes, the development and use of technology can mitigate their effects. Waves generated by earthquakes travel through Earth and can be detected by seismometers and other scientific instruments. KEY TERMS Earthquake Vibrations within Earth caused by the sudden release of energy, usually as a result of the movement of rocks along a fault. Seismograph An instrument used to detect earthquake waves. Seismology The study of earthquakes and seismic phenomena. Seismometer An instrument used to detect earthquake waves. Body wave An earthquake wave that travels through the body of Earth rather than on its surface. See also P-wave, S-wave, and surface wave. Seismic station the place where a permanent installation of a seismic sensor/seismic recorder (seismometer/seismograph) is located. Surface wave An earthquake wave that travels at or near the surface of Earth. Model A tool scientists and engineers use to represent ideas or provide an explanation. Models may include diagrams, drawings, physical replicas, mathematical representations, analogies, or computer simulations. S-wave A secondary earthquake wave, so named because it travels slower than a primary wave and is the second wave to reach the seismograph station after an earthquake. It travels through the body of Earth as a series of crests and troughs. P-wave A primary (compressional) earthquake wave that travels through the body of Earth; so named because it is the first wave to reach a seismograph station during an earthquake. Force A push or pull between objects Aftershock : An earthquake that occurs later along the same fault zone as a major earthquake, but before the area has returned to its normal level of seismic activity. Seismogram The record made by a seismograph; the paper on which data about earthquake waves is recorded. Globe A spherical model of Earth Map A representation of Earth (or part of Earth), usually on a flat surface Tsunami A series of sea waves caused by undersea events, such as an earthquake beneath the ocean floor, that rise to great heights as they near a shore. Epicenter Location on Earth’s surface directly above an earthquake’s focus, or origin. Focus Location beneath Earth’s surface where the energy of an earthquake is released. Magnitude A measure of the total amount of energy released at the focus of an earthquake. Mitigate To make less severe, intense, or painful Risk Exposure to the chance of injury or loss. Asthenosphere The layer of the mantle that lies directly below the lithosphere and flows very, very slowly on long timescales. Intensity A measure of the damage done by an earthquake that is determined on the basis of the earthquake’s effect on people, structures, and the natural environment. Plate A large, mobile segment of Earth’s lithosphere. Core Earth’s innermost layers, consisting of a liquid iron outer core and a solid iron-nickel inner core. See also crust, and mantle. Lithosphere The cool, solid outer shell of Earth. It consists of the crust and the rigid uppermost part of the mantle and is broken up into segments, or plates. Plate tectonics A theory that the lithosphere is broken into segments, or plates, that “float” on the asthenosphere, and that interactions among these plates are associated with earthquakes and volcanic activity and form mid-ocean ridges, trenches, mountains, and chains of volcanic islands. Crust Earth’s outer layer; the coolest and least dense layer of Earth. See also core, and mantle. Mantle The layer of Earth beneath the crust. It is about 2,900 km (1,800 mi) thick, and makes up about 83 percent of Earth’s interior. See also core, and crust. Rocks Naturally forming material that is usually made of up two or more distinct minerals. See also igneous rock, metamorphic rock, and sedimentary rock Friction A force that opposes the motion of objects, which are in contact.