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Earthquakes
Term | Definition |
---|---|
Earthquake | A sudden and violent shaking of the ground, sometimes causing great destruction |
Crust | The tough outer part of the Earth. |
Fault | A break in the Earth's crust that was cused by an earthquake. |
Mantle | The region of the earth's interior between the crust and the core, believed to consist of hot, dense silicate rocks |
Lithosphere | The rigid outer part of the earth, consisting of the crust and upper mantle. |
Lithospheric Plates | Regions of Earth's crust and upper mantle that are fractured into plates that move across a deeper plasticine mantle. |
Seismiologists | Scientific study of earthquakes and the propagation of elastic waves through the Earth or through other planet-like bodies. |
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. |
Moment-Magnitude Scale | 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. |
Mercalli Scale | The Mercalli intensity scale is a seismic scale used for measuring the intensity of 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 level of shaking from the earthquake. |
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. |
Flexible Pipe | Flexible pipes bend as energy passes through them, greatly reducing damage. |
Aftershock | Smaller erthquakes after the major earthquake that could be hours, days, or even months after. |
Tsunami | A tsunami, also known as a seismic sea wave, is a series of waves in a water body caused by the displacement of a large volume of water, generally in an ocean or a large lake. |
Base Isolator | Base Isolators separate or isolate from its foundation and prevent some energy from the earthquake entering the building. |
Shear Core Walls | A shear wall transfers some of a quake’s energy from roofs and floors to the building foundation. |
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. |
Cross Bracing | Steel Cross Braces are placed between stories to stiffen a building’s frame and absorb during energy an earthquake. |
Mass Damper | These are things that work like the shock absorbs in a car to absorb some of the energy of seismic waves. |
Compression | It is the stress component perpendicular to a given surface, such as a fault plane, that results from forces applied perpendicular to the surface or from remote forces transmitted through the surrounding rock. |
Tension | Apply a force to (something) that tends to stretch it. |
Stress | Pressure or tension exerted on a material object. |
Strike-Slip Fault | Strike-slip faults have a different type of movement than normal and reverse faults. |
Normal Fault | A normal fault drops rock on one side of the fault down relative to the other side. Take a look at the side that shows the fault and arrows indicating movement. |
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 (810 miles) through California. |
Plateau | An area of relatively level high ground. |
Hanging Wall | Hanging Wall is the block positioned over the fault, the Foot Wall is the block positioned under it. |
Footwall | the block of rock that lies on the underside of an inclined fault or of a mineral deposit. |
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 | The upper layer of the earth's mantle, below the lithosphere, in which there is relatively low resistance to plastic flow and convection is thought to occur. |
Inner Core | The Earth's inner core is the Earth's innermost part. |
Outer Core | The outer core of the Earth is a liquid layer about 2,300 km thick and composed of iron and nickel that lies above Earth's solid inner core and below its mantle. |
Lithosphere | The rigid outer part of the earth, consisting of the crust and upper mantle. |