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Earthquake 1
science
Term | Definition |
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Earthquake | An earthquake is a shaking of the ground caused by the sudden breaking and movement of large sections (tectonic plates) of the earth's rocky outermost crust. |
Crust | the crust is the outermost solid shell of a rocky planet or natural satellite, which is chemically distinct from the underlying mantle. |
Fault | A fault is a crack in the Earth's crust. Typically, faults are associated with, or form, the boundaries between Earth's tectonic plates. In an active fault, the pieces of the Earth's crust along a fault move over time. |
Mantle | the portion of the earth, about 1800 miles (2900 km) thick, between the crust and the core. |
Lithosphere | the rigid outer part of the earth, consisting of the crust and upper mantle. |
Lithospheric Plates | The lithosphere is broken into a series of moving plates. The boundary between two plates can be a divergent boundary, a convergent boundary or a transform boundary. |
Seismologists | Seismology is the study of seismic waves, energy waves caused by rock suddenly breaking apart within the earth or the slipping of tectonic plates. |
P-Waves | P-waves are a type of body wave, called seismic waves in seismology, that travel through a continuum and are the first waves from an earthquake to arrive at a seismograph. |
S-Waves | An S wave, or shear wave, is a seismic body wave that shakes the ground back and forth perpendicular to the direction the wave is moving. |
Surface Waves | Surface waves, in this mechanical sense, are commonly known as either Love waves (L waves) or Rayleigh waves. A seismic wave is a wave that travels through the Earth, often as the result of an earthquake or explosion. |
Focus | The point on the Earth's surface located directly above the focus of an earthquake. |
Epicenter | a point, directly above the true center of disturbance, from which the shock waves of an earthquake apparently radiate. |
Richter Scale | The Richter scale, developed in the 1930s, is a base-10 logarithmic scale, which defines magnitude as the logarithm of the ratio of the amplitude of the seismic waves to an arbitrary, minor amplitude. |
Movment-Magnitude | The moment magnitude scale (abbreviated as MMS; denoted as MW or M) is used by seismologists to measure the size of earthquakes in terms of the energy released. |
Mercallli Scale | The Mercalli intensity scale is a seismic scale used for measuring the intensity of an earthquake. It measures the effects of an earthquake, and is distinct from the moment magnitude usually reported for an earthquake. |
Seismic Waves | Seismic waves are waves of energy that travel through the Earth's layers, and are a result of an earthquake, explosion, or a volcano that gives out low-frequency acoustic energy. |
Magnitude | The great size or extent of something. |
Seismograph | An instrument that measures and records details of earthquakes, such as force and duration. |
Liquefaction | Liquefaction is a phenomenon in which the strength and stiffness of a soil is reduced by earthquake shaking or other rapid loading. |
Aftershock | An aftershock is a smaller earthquake that occurs after a previous large earthquake, in the same area of the main shock. |
Base Isolators | Base isolation is one of the most powerful tools of earthquake engineering pertaining to the passive structural vibration control technologies. |
Flexible Piping | Flexible pipes bend as energy passes through them, greatly reducing damage. |
Shear Core/Walls | A shear wall transfers some of a quake’s energy from roofs and floors to the building’s foundation. |
Cross Bracing | Steel cross braces are placed between stories to stiffen a building’s frame and absorb energy during an earthquake |
Tension Ties | These devices firmly “tie” the floors and ceilings of a building to the walls.Tension ties absorb and scatter earthquake energy and thus reduce damage. |
Mass Damper | Dampers work like the shock absorbs in a car to absorb some of the energy of seismic waves. |
Compression | Pushes rock together. |
Tension | Streches rock. |
Stress | Stresses occur in the crust working over millions of years to change shape and volume of rock. |
Strike-Slip-Fault | If the block opposite an observer looking across the fault moves to the right, the slip style is termed right lateral; if the block moves to the left, the motion is termed left lateral. |
Normal Fault | A thrust fault is a reverse fault with a dip of 45 degrees or less. Oblique-slip faults have significant components of different slip styles. |
Reverse Fault | Along a reverse fault one rocky block is pushed up relative to rock on the other side. |
Shearing | Shear stress is the stress component parallel to a given surface, such as a fault plane, that results from forces applied parallel to the surface or from remote forces transmitted through the surrounding rock. |
San Andreas Fault | The San Andreas Fault is a continental transform fault that extends roughly 1300 km through California. It forms the tectonic boundary between the Pacific Plate and the North American Plate. |
Plateau | An area of relatively level high ground. |
Hanging Wall | The Hanging Wall is the block positioned over the fault, the Foot Wall is the block positioned under it. |
Footwall | The rocks on the lower side of an inclined fault plane or mineral vein. Compare hanging wall |
Anticline | Anticlines are folds in which each half of the fold dips away from the crest. |
Syncline | Synclines are folds in which each half of the fold dips toward the trough of the fold. |
Asthenosphere | Mechanically weak and ductilely deforming region of the upper mantle of the Earth. It lies below the lithosphere, at depths between approximately 80 and 200 km (50 and 120 miles) below the surface. |
Mantle | It is the part of the earth between the core and the the crust is the MANTLE.The mantle is made up of magma and rock. |
Crust | The outer layer of the Earth, between the surface and the mantle, which is up to 40 miles deep. |
Inner Core | The inner core, at the center of the earth, made of iron. |
Outer Core | The outer core, which surrounds the inner core, made of iron and magma. |
Lithosphere | The lithosphere is the solid outer section of Earth, which includes Earth's crust (the "skin" of rock on the outer layer of planet Earth), as well as the underlying cool, dense, and rigid upper part of the upper mantle. |