Earthquake

earthquakesseismic activityseismictremorsearth tremorearthshakeseismicityseismic eventseismically activeearth tremors
An earthquake (also known as a quake, tremor or temblor) is the shaking of the surface of the Earth, resulting from the sudden release of energy in the Earth's lithosphere that creates seismic waves.wikipedia
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Seismicity

seismically activeseismic
The seismicity, or seismic activity, of an area is the frequency, type and size of earthquakes experienced over a period of time.
Seismicity is a measure which encompasses earthquake occurrences, mechanisms, and magnitude at a given geographical location.

Episodic tremor and slip

non-earthquake seismic rumbling
The word tremor is also used for non-earthquake seismic rumbling.
Episodic tremor and slip (ETS) is a seismological phenomenon observed in some subduction zones that is characterized by non-earthquake seismic rumbling, or tremor, and slow slip along the plate interface.

Landslide

landslideslandslipdebris avalanche
Earthquakes can also trigger landslides, and occasionally volcanic activity.
In many cases, the landslide is triggered by a specific event (such as a heavy rainfall, an earthquake, a slope cut to build a road, and many others), although this is not always identifiable.

Seismic wave

seismic wavesseismic velocitybody waves
An earthquake (also known as a quake, tremor or temblor) is the shaking of the surface of the Earth, resulting from the sudden release of energy in the Earth's lithosphere that creates seismic waves.
Seismic waves are waves of energy that travel through the Earth's layers, and are a result of earthquakes, volcanic eruptions, magma movement, large landslides and large man-made explosions that give out low-frequency acoustic energy.

Megathrust earthquake

megathrustmegathrust typemegathrust earthquakes
Reverse faults, particularly those along convergent plate boundaries are associated with the most powerful earthquakes, megathrust earthquakes, including almost all of those of magnitude 8 or more.
Since 1900, all earthquakes of magnitude 9.0 or greater have been megathrust earthquakes.

Fault (geology)

faultfaultsstrike-slip
Earthquakes are caused mostly by rupture of geological faults, but also by other events such as volcanic activity, landslides, mine blasts, and nuclear tests.
Energy release associated with rapid movement on active faults is the cause of most earthquakes.

Interplate earthquake

interplate
There are three main types of fault, all of which may cause an interplate earthquake: normal, reverse (thrust) and strike-slip.
An interplate earthquake is an earthquake that occurs at the boundary between two tectonic plates.

Elastic-rebound theory

elastic reboundelastic rebound theoryelastic strain energy
This process of gradual build-up of strain and stress punctuated by occasional sudden earthquake failure is referred to as the elastic-rebound theory.
In geology, the elastic-rebound theory is an explanation for how energy is released during an earthquake.

Focal mechanism

moment tensor solutionfault plane solutionFault-plane solutions
This is demonstrated by earthquake focal mechanisms.
The focal mechanism of an earthquake describes the deformation in the source region that generates the seismic waves.

Earth

terrestrialworldGlobal
An earthquake (also known as a quake, tremor or temblor) is the shaking of the surface of the Earth, resulting from the sudden release of energy in the Earth's lithosphere that creates seismic waves.
Along these plate boundaries, earthquakes, volcanic activity, mountain-building, and oceanic trench formation can occur.

Aseismic creep

aseismicfault creepaseismic sliding
The sides of a fault move past each other smoothly and aseismically only if there are no irregularities or asperities along the fault surface that increase the frictional resistance.
In geology, aseismic creep or fault creep is measurable surface displacement along a fault in the absence of notable earthquakes.

Deep-focus earthquake

deep focus earthquakedeep-focusdeep focus
In subduction zones, where older and colder oceanic crust descends beneath another tectonic plate, Deep-focus earthquakes may occur at much greater depths (ranging from ).
A deep-focus earthquake in seismology (also called a plutonic earthquake) is an earthquake with a hypocenter depth exceeding 300 km. They occur almost exclusively at convergent boundaries in association with subducted oceanic lithosphere.

Subduction

subduction zonesubductedsubducting
In subduction zones, where older and colder oceanic crust descends beneath another tectonic plate, Deep-focus earthquakes may occur at much greater depths (ranging from ).
Subduction zones are sites that usually have a high rate of volcanism and earthquakes.

Supershear earthquake

supershearabove the S-wave velocity
These supershear earthquakes have all been observed during large strike-slip events.
A supershear earthquake is an earthquake in which the propagation of the rupture along the fault surface occurs at speeds in excess of the seismic shear wave (S-wave) velocity.

Slow earthquake

slippageSlowslow slip
Some earthquake ruptures travel at unusually low velocities and are referred to as slow earthquakes.
A slow earthquake is a discontinuous, earthquake-like event that releases energy over a period of hours to months, rather than the seconds to minutes characteristic of a typical earthquake.

Transform fault

transform boundarytransformtransform faults
Strike-slip faults, particularly continental transforms, can produce major earthquakes up to about magnitude 8.
Slip along transform faults does not increase the distance between the ridges it separates; the distance remains constant in earthquakes because the ridges are spreading centers.

Foreshock

fore-precursor earthquakes
If an aftershock is larger than the main shock, the aftershock is redesignated as the main shock and the original main shock is redesignated as a foreshock.
A foreshock is an earthquake that occurs before a larger seismic event (the mainshock) and is related to it in both time and space.

Wadati–Benioff zone

Benioff zoneBenioff zonesinclined seismic zones
These seismically active areas of subduction are known as Wadati–Benioff zones.
Differential motion along the zone produces numerous earthquakes, the foci of which may be as deep as about 670 kilometres.

Aftershock

aftershocksOmori's lawOmori law
They are different from earthquakes followed by a series of aftershocks by the fact that no single earthquake in the sequence is obviously the main shock, therefore none have notable higher magnitudes than the other.
An aftershock is a smaller earthquake that follows a larger earthquake, in the same area of the main shock, caused as the displaced crust adjusts to the effects of the main shock.

Seismic intensity scales

seismic intensity scale
Prior to the development of strong-motion accelerometers that can measure peak ground speed and acceleration directly, the intensity of the earth-shaking was estimated on the basis of the observed effects, as categorized on various seismic intensity scales.
Seismic intensity scales categorize the intensity or severity of ground shaking (quaking) at a given location, such as resulting from an earthquake.

Tsunami earthquake

category of earthquakesTsunamitsunami events
A particularly dangerous form of slow earthquake is the tsunami earthquake, observed where the relatively low felt intensities, caused by the slow propagation speed of some great earthquakes, fail to alert the population of the neighboring coast, as in the 1896 Sanriku earthquake.
Such events are a result of relatively slow rupture velocities.

Charles Francis Richter

Charles RichterCharles F. RichterRichter, Charles Francis
The first scale for measuring earthquake magnitudes was developed by Charles F. Richter in 1935.
Richter is most famous as the creator of the Richter magnitude scale, which, until the development of the moment magnitude scale in 1979, quantified the size of earthquakes.

Accelerograph

accelerogramstrong-motion accelerometers
Prior to the development of strong-motion accelerometers that can measure peak ground speed and acceleration directly, the intensity of the earth-shaking was estimated on the basis of the observed effects, as categorized on various seismic intensity scales.
An accelerograph can be referred to as a strong-motion instrument or seismograph, or simply an earthquake accelerometer.

1957 Andreanof Islands earthquake

19571957 Andreanof Islands (M8.6)1957 Andreanof Islands earthquake and tsunami
Examples are the earthquakes in Chile, 1960; Alaska, 1957; Sumatra, 2004, all in subduction zones.
In Alaska, the earthquake caused severe damage to roads and buildings on Adak Island, but no lives were lost.

Ring of Fire

Pacific Ring of Firecircum-Pacific orogenic beltPacific Rim
Most of the world's earthquakes (90%, and 81% of the largest) take place in the 40000 km long, horseshoe-shaped zone called the circum-Pacific seismic belt, known as the Pacific Ring of Fire, which for the most part bounds the Pacific Plate.
The Ring of Fire is a major area in the basin of the Pacific Ocean where many earthquakes and volcanic eruptions occur.