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2014 Aegean Sea Earthquake
An earthquake occurred in the northern Aegean Sea between Greece and Turkey on May 24, 2014. It had a moment magnitude of 6.9 and a maximum Mercalli intensity scale, Mercalli intensity of VIII (''Severe''). Serious damage was reported on the Turkish island of Imbros and the cities of Edirne and Çanakkale, as well as on the Greek island of Lemnos. The earthquake was felt in Bulgaria and southern Romania. Several aftershocks followed the main shock, the strongest measuring 5.3 ML. This aftershock struck the Gulf of Saros at 12:31 local time. Tectonic setting The northern part of the Aegean Sea shows a transition from the strike-slip tectonics associated with the North Anatolian Fault (NAF) to the extensional tectonics that characterise the area north of the Hellenic arc. The location of this earthquake is on the westward continuation of the NAF on the boundary between the Anatolian Plate and the Eurasian Plate. Other earthquakes on this part of the NAF include an M6.6 event in 19 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United States Geological Survey
The United States Geological Survey (USGS), formerly simply known as the Geological Survey, is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its natural resources, and the natural hazards that threaten it. The organization's work spans the disciplines of biology, geography, geology, and hydrology. The USGS is a fact-finding research organization with no regulatory responsibility. The agency was founded on March 3, 1879. The USGS is a bureau of the United States Department of the Interior; it is that department's sole scientific agency. The USGS employs approximately 8,670 people and is headquartered in Reston, Virginia. The USGS also has major offices near Lakewood, Colorado, at the Denver Federal Center, and Menlo Park, California. The current motto of the USGS, in use since August 1997, is "science for a changing world". The agency's previous slogan, adopted on the occasion of its hundredt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gulf Of Saros
Saros Bay or Gulf of Saros ( tr, Saros Körfezi; el, κόλπος του Σάρρου) is a gulf in the Dardanelles, Turkey. Ancient Greeks called it the Gulf of Melas (), before it was renamed. The bay is long and wide. Far from industrialized areas and thanks to underwater currents, it is a popular summer recreation resort with sandy strands and crystal-clear sea. Scuba diving, windsurfing and fishing are the most practiced water sports here. Settlements around the bay are: Gökçetepe, Mecidiye, Edirne, Mecidiye, Erikli, Danişment, Yayla, Karaincirli, Vakıf, Büyükevren, Sultaniçe, Gülçavuş and Enez, all in Edirne Province. The islands of Gökçeada (Imbros) lie outside Saros Bay and Samothrace in the Aegean Sea, Greece, is in short distance. The North Anatolian Fault Zone, the most prominent active fault in Turkey and the source of numerous large earthquakes throughout history, passes through the Gulf of İzmit and traverses the Marmara Sea reaching to the Saros ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
USGS Shakemap - 2014 Aegean Sea Earthquake
The United States Geological Survey (USGS), formerly simply known as the Geological Survey, is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its natural resources, and the natural hazards that threaten it. The organization's work spans the disciplines of biology, geography, geology, and hydrology. The USGS is a fact-finding research organization with no regulatory responsibility. The agency was founded on March 3, 1879. The USGS is a bureau of the United States Department of the Interior; it is that department's sole scientific agency. The USGS employs approximately 8,670 people and is headquartered in Reston, Virginia. The USGS also has major offices near Lakewood, Colorado, at the Denver Federal Center, and Menlo Park, California. The current motto of the USGS, in use since August 1997, is "science for a changing world". The agency's previous slogan, adopted on the occasion of its hundredth anniversa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Supershear Earthquake
In seismology, 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. This causes an effect analogous to a sonic boom. Rupture propagation velocity During seismic events along a fault surface the displacement initiates at the focus and then propagates outwards. Typically for large earthquakes the focus lies towards one end of the slip surface and much of the propagation is unidirectional (e.g. the 2008 Sichuan and 2004 Indian Ocean earthquakes). Theoretical studies have in the past suggested that the upper bound for propagation velocity is that of Rayleigh waves, approximately 0.92 of the shear wave velocity. However, evidence of propagation at velocities between S-wave and compressional wave (P-wave) values have been reported for several earthquakesArchuleta,R.J. 1984A faulting model for the 1979 Imperial Valley earthquake J. Geophys. Res., 89, 4559–4585. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
S-wave
__NOTOC__ In seismology and other areas involving elastic waves, S waves, secondary waves, or shear waves (sometimes called elastic S waves) are a type of elastic wave and are one of the two main types of elastic body waves, so named because they move through the body of an object, unlike surface wave In physics, a surface wave is a mechanical wave that propagates along the Interface (chemistry), interface between differing media. A common example is gravity waves along the surface of liquids, such as ocean waves. Gravity waves can also occu ...s. S waves are transverse waves, meaning that the direction of particle motion of a S wave is perpendicular to the direction of wave propagation, and the main restoring force comes from shear stress. Therefore, S waves cannot propagate in liquids with zero (or very low) viscosity; however, they may propagate in liquids with high viscosity. The name ''secondary wave'' comes from the fact that they are the second type of wave to be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hypocenter
In seismology, a hypocenter or hypocentre () is the point of origin of an earthquake or a subsurface nuclear explosion. A synonym is the focus of an earthquake. Earthquakes An earthquake's hypocenter is the position where the strain energy stored in the rock is first released, marking the point where the fault begins to rupture.''The hypocenter is the point within the earth where an earthquake rupture starts. The epicenter is the point directly above it at the surface of the Earth. Also commonly termed the focus.'' This occurs directly beneath the epicenter, at a distance known as the ''hypocentral depth'' or ''focal depth''. The focal depth can be calculated from measurements based on seismic wave phenomena. As with all wave phenomena in physics, there is uncertainty in such measurements that grows with the wavelength so the focal depth of the source of these long-wavelength (low frequency) waves is difficult to determine exactly. Very strong earthquakes radiate a large fr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Strong Ground Motion
In seismology, strong ground motion is the strong earthquake shaking that occurs close to (less than about 50 km from) a causative fault. The strength of the shaking involved in strong ground motion usually overwhelms a seismometer, forcing the use of accelerographs (or strong ground motion accelerometers) for recording. The science of strong ground motion also deals with the variations of fault rupture, both in total displacement, energy released, and rupture velocity. As seismic instruments (and accelerometers in particular) become more common, it becomes necessary to correlate expected damage with instrument-readings. The old Modified Mercalli intensity scale (MM), a relic of the pre-instrument days, remains useful in the sense that each intensity-level provides an observable difference in seismic damage. After many years of trying every possible manipulation of accelerometer-time histories, it turns out that the extremely simple peak ground velocity (PGV) provides th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dip And Strike
Strike and dip is a measurement convention used to describe the orientation, or attitude, of a planar geologic feature. A feature's strike is the azimuth of an imagined horizontal line across the plane, and its dip is the angle of inclination measured downward from horizontal. They are used together to measure and document a structure's characteristics for study or for use on a geologic map. A feature's orientation can also be represented by dip and dip direction, using the azimuth of the dip rather than the strike value. Linear features are similarly measured with trend and plunge, where "trend" is analogous to dip direction and "plunge" is the dip angle. Strike and dip are measured using a compass and a clinometer. A compass is used to measure the feature's strike by holding the compass horizontally against the feature. A clinometer measures the features dip by recording the inclination perpendicular to the strike. These can be done separately, or together using a tool such as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Focal Mechanism
The focal mechanism of an earthquake describes the deformation in the source region that generates the seismic waves. In the case of a fault-related event it refers to the orientation of the fault plane that slipped and the slip vector and is also known as a fault-plane solution. Focal mechanisms are derived from a solution of the moment tensor for the earthquake, which itself is estimated by an analysis of observed seismic waveforms. The focal mechanism can be derived from observing the pattern of "first motions", that is, whether the first arriving P waves break up or down. This method was used before waveforms were recorded and analysed digitally and this method is still used for earthquakes too small for easy moment tensor solution. Focal mechanisms are now mainly derived using semi-automatic analysis of the recorded waveforms. Moment tensor solutions The moment tensor solution is typically displayed graphically using a so-called ''beachball'' diagram. The pattern of en ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eurasian Plate
The Eurasian Plate is a tectonic plate that includes most of the continent of Eurasia (a landmass consisting of the traditional continents of Europe and Asia), with the notable exceptions of the Indian subcontinent, the Arabian subcontinent and the area east of the Chersky Range in eastern Siberia. It also includes oceanic crust extending westward to the Mid-Atlantic Ridge and northward to the Gakkel Ridge. The eastern edge is a boundary with the North American Plate to the north and a boundary with the Philippine Sea Plate to the south and possibly with the Okhotsk Plate and the Amurian Plate. The southern edge is a boundary with the African Plate to the west, the Arabian Plate in the middle and the Indo-Australian Plate to the east. The western edge is a divergent boundary with the North American Plate forming the northernmost part of the Mid-Atlantic Ridge, which is straddled by Iceland. All volcanic eruptions in Iceland, such as the 1973 eruption of Eldfell, the 1783 eruptio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anatolian Plate
The Anatolian Plate is a continental tectonic plate comprising most of the Anatolia (Asia Minor) peninsula (and the country of Turkey). To the east, the East Anatolian Fault, a left lateral transform fault, forms a boundary with the Arabian Plate. To the south and southwest is a convergent boundary with the African Plate. This convergence manifests in compressive features within the oceanic crust beneath the Mediterranean as well as within the continental crust of Anatolia itself, and also by what are generally considered to be subduction zones along the Hellenic and Cyprus arcs. The northern edge is a transform boundary with the Eurasian Plate, forming the North Anatolian Fault Zone (NAFZ). Research indicates that the Anatolian Plate is rotating counterclockwise as it is being pushed west by the Arabian Plate, impeded from any northerly movement by the Eurasian Plate. In some references, the Anatolian Plate is referred to as a "block" of continental crust still coupled to t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hellenic Arc
The Hellenic arc or Aegean arc is an arcuate mountain chain of the southern Aegean Sea located on the southern margin of the Aegean Sea Plate. Geologically it results from the subduction of the African Plate under it along the Hellenic subduction zone. The Hellenic Trench trends parallel to its southern side. The Aegean Sea Plate, a microplate, is often considered part of the Eurasian Plate from which it is in the process of diverging. The arc itself is mainly marine, the mountaintops appearing as islands in the Ionian Sea, Crete and its environs, or in the Dodecanese group. It encroaches on mainland terrain in the Peloponnesus, on Crete, on Rhodes, and on the southern coast of Anatolia, thus being encompassed by both Greece and Turkey. The direction of subduction is northward. Locations on the arc or near it on the north side are therefore called "outer" as they are at the outer margin of the plate. Locations further north are "inner." Generally the motion of subduction is from ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
