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2017 Central Mexico Earthquake
The 2017 Puebla earthquake struck at 13:14 CDT (18:14 UTC) on 19 September 2017 with an estimated magnitude of and strong shaking for about 20 seconds. Its epicenter was about south of the city of Puebla, Mexico. The earthquake caused damage in the Mexican states of Puebla and Morelos and in the Greater Mexico City area, including the collapse of more than 40 buildings. 370 people were killed by the earthquake and related building collapses, including 228 in Mexico City, and more than 6,000 were injured. The quake coincidentally occurred on the 32nd anniversary of the 1985 Mexico City earthquake, which killed around 10,000 people. The 1985 quake was commemorated, and a national earthquake drill was held, at 11 a.m. local time, just two hours before the 2017 earthquake. Twelve days earlier, the even larger 2017 Chiapas earthquake struck away, off the coast of the state of Chiapas. Background Mexico is one of the world's most seismically active regions, sitting ato ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Moment Magnitude Scale
The moment magnitude scale (MMS; denoted explicitly with or Mw, and generally implied with use of a single M for magnitude) is a measure of an earthquake's magnitude ("size" or strength) based on its seismic moment. It was defined in a 1979 paper by Thomas C. Hanks and Hiroo Kanamori. Similar to the local magnitude scale, local magnitude/Richter scale () defined by Charles Francis Richter in 1935, it uses a logarithmic scale; small earthquakes have approximately the same magnitudes on both scales. Despite the difference, news media often says "Richter scale" when referring to the moment magnitude scale. Moment magnitude () is considered the authoritative magnitude scale for ranking earthquakes by size. It is more directly related to the energy of an earthquake than other scales, and does not saturate—that is, it does not underestimate magnitudes as other scales do in certain conditions. It has become the standard scale used by seismological authorities like the U.S. Geological ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Associated Press
The Associated Press (AP) is an American non-profit news agency headquartered in New York City. Founded in 1846, it operates as a cooperative, unincorporated association. It produces news reports that are distributed to its members, U.S. newspapers and broadcasters. The AP has earned 56 Pulitzer Prizes, including 34 for photography, since the award was established in 1917. It is also known for publishing the widely used '' AP Stylebook''. By 2016, news collected by the AP was published and republished by more than 1,300 newspapers and broadcasters, English, Spanish, and Arabic. The AP operates 248 news bureaus in 99 countries. It also operates the AP Radio Network, which provides newscasts twice hourly for broadcast and satellite radio and television stations. Many newspapers and broadcasters outside the United States are AP subscribers, paying a fee to use AP material without being contributing members of the cooperative. As part of their cooperative agreement with the AP, most ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
The Washington Post
''The Washington Post'' (also known as the ''Post'' and, informally, ''WaPo'') is an American daily newspaper published in Washington, D.C. It is the most widely circulated newspaper within the Washington metropolitan area and has a large national audience. Daily broadsheet editions are printed for D.C., Maryland, and Virginia. The ''Post'' was founded in 1877. In its early years, it went through several owners and struggled both financially and editorially. Financier Eugene Meyer purchased it out of bankruptcy in 1933 and revived its health and reputation, work continued by his successors Katharine and Phil Graham (Meyer's daughter and son-in-law), who bought out several rival publications. The ''Post'' 1971 printing of the Pentagon Papers helped spur opposition to the Vietnam War. Subsequently, in the best-known episode in the newspaper's history, reporters Bob Woodward and Carl Bernstein led the American press's investigation into what became known as the Watergate scandal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coulomb Stress Transfer
Coulomb stress transfer is a seismic-related geological process of stress changes to surrounding material caused by local discrete deformation events. Using mapped displacements of the Earth's surface during earthquakes, the computed Coulomb stress changes suggest that the stress relieved during an earthquake not only dissipates but can also move up and down fault segments, concentrating and promoting subsequent tremors. Importantly, Coulomb stress changes have been applied to earthquake-forecasting models that have been used to assess potential hazards related to earthquake activity. Coulomb stress change The Coulomb failure criterion requires that the Coulomb stress exceeds a value σf defined by the shear stress τB, normal stress σB, pore pressure p, and coefficient of friction μ of a failure plane, such that It is also often assumed that changes in pore fluid pressure induced by changes in stress are proportional to the normal stress change across the fault plane. These ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Remotely Triggered Earthquakes
Remotely triggered earthquakes are a result of the effects of large earthquakes at considerable distance, outside of the immediate aftershock zone. The farther one gets from the initiating earthquake in both space and time, the more difficult it is to establish an association. The physics of triggering an earthquake are complex. Most earthquake-generating zones are in a state of being close to failure. If such a zone were to be left completely alone, it would generate significant earthquakes spontaneously. Remote earthquakes, however, are in a position to disturb this critical state, either by shifting the stresses statically, or by dynamic change caused by passing seismic waves. The first type of triggering may be due to static changes in the critical state. For example, after the magnitude 7.3 Landers earthquake struck California in 1992, it is said that "the earthquake map of California lit up like a Christmas tree". This event reinforced the idea of remotely triggered earthqua ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aftershock
In seismology, 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. Large earthquakes can have hundreds to thousands of instrumentally detectable aftershocks, which steadily decrease in magnitude and frequency according to a consistent pattern. In some earthquakes the main rupture happens in two or more steps, resulting in multiple main shocks. These are known as doublet earthquakes, and in general can be distinguished from aftershocks in having similar magnitudes and nearly identical seismic waveforms. Distribution of aftershocks Most aftershocks are located over the full area of fault rupture and either occur along the fault plane itself or along other faults within the volume affected by the strain associated with the main shock. Typically, aftershocks are found up to a distance equal to the rupture length away from the fault plane. The pattern ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Los Angeles Times
The ''Los Angeles Times'' (abbreviated as ''LA Times'') is a daily newspaper that started publishing in Los Angeles in 1881. Based in the LA-adjacent suburb of El Segundo since 2018, it is the sixth-largest newspaper by circulation in the United States. The publication has won more than 40 Pulitzer Prizes. It is owned by Patrick Soon-Shiong and published by the Times Mirror Company. The newspaper’s coverage emphasizes California and especially Southern California stories. In the 19th century, the paper developed a reputation for civic boosterism and opposition to labor unions, the latter of which led to the bombing of its headquarters in 1910. The paper's profile grew substantially in the 1960s under publisher Otis Chandler, who adopted a more national focus. In recent decades the paper's readership has declined, and it has been beset by a series of ownership changes, staff reductions, and other controversies. In January 2018, the paper's staff voted to unionize and final ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lake Texcoco
Lake Texcoco ( es, Lago de Texcoco) was a natural lake within the "Anahuac" or Valley of Mexico. Lake Texcoco is best known as where the Aztecs built the city of Tenochtitlan, which was located on an island within the lake. After the Spanish conquest of the Aztec Empire, efforts to control flooding by the Spanish led to most of the lake being drained. The entire lake basin is now almost completely occupied by Mexico City, the capital of the present-day nation of Mexico. Drainage of the lake has led to serious ecological and human consequences: the local climate and water availability have changed considerably, contributing to water scarcity in the area; subsequent groundwater extraction leads to land subsidence under much of the city; and native species endemic to the lake region have become severely endangered or extinct due to ecosystem change, such as the axolotl. After the cancellation of the Mexico City Texcoco Airport, the government initiated a major restoration project ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Caribbean
The Caribbean (, ) ( es, El Caribe; french: la Caraïbe; ht, Karayib; nl, De Caraïben) is a region of the Americas that consists of the Caribbean Sea, its islands (some surrounded by the Caribbean Sea and some bordering both the Caribbean Sea and the North Atlantic Ocean) and the surrounding coasts. The region is southeast of the Gulf of Mexico and the North American mainland, east of Central America, and north of South America. Situated largely on the Caribbean Plate, the region has more than 700 islands, islets, reefs and cays (see the list of Caribbean islands). Island arcs delineate the eastern and northern edges of the Caribbean Sea: The Greater Antilles and the Lucayan Archipelago on the north and the Lesser Antilles and the on the south and east (which includes the Leeward Antilles). They form the West Indies with the nearby Lucayan Archipelago (the Bahamas and Turks and Caicos Islands), which are considered to be part of the Caribbean despite not bordering the Caribbe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rivera Plate
The Rivera Plate is a small tectonic plate (a microplate) located off the west coast of Mexico, just south of the Baja California Peninsula. It is bounded on the northwest by the East Pacific Rise, on the southwest by the Rivera Transform Fault, on the southeast by a deformation zone, and on the northeast by the Middle America Trench and another deformation zone. The Rivera Plate is believed to have separated from the Cocos Plate located to its southeast about 5–10 million years ago. Seismicity and tomography images show that the Rivera plate dips at 40° beneath the forearc region and then dips ~70° beneath the Trans-Mexican Volcanic Belt. The subduction of the Rivera Plate under the North American Plate, in the Mid-American Trench, has been the cause of the strongest earthquakes in the history of Mexico, including the largest earthquake in Mexico during the 20th century which occurred on June 3, 1932 in the state of Jalisco. The quake had a magnitude of 8.2 with a magnit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Subduction Zone
Subduction is a geological process in which the oceanic lithosphere is recycled into the Earth's mantle at convergent boundaries. Where the oceanic lithosphere of a tectonic plate converges with the less dense lithosphere of a second plate, the heavier plate dives beneath the second plate and sinks into the mantle. A region where this process occurs is known as a subduction zone, and its surface expression is known as an arc-trench complex. The process of subduction has created most of the Earth's continental crust. Rates of subduction are typically measured in centimeters per year, with the average rate of convergence being approximately two to eight centimeters per year along most plate boundaries. Subduction is possible because the cold oceanic lithosphere is slightly denser than the underlying asthenosphere, the hot, ductile layer in the upper mantle underlying the cold, rigid lithosphere. Once initiated, stable subduction is driven mostly by the negative buoyancy of the dens ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
North American Plate
The North American Plate is a tectonic plate covering most of North America, Cuba, the Bahamas, extreme northeastern Asia, and parts of Iceland and the Azores. With an area of , it is the Earth's second largest tectonic plate, behind the Pacific Plate (which borders the plate to the west). It extends eastward to the Mid-Atlantic Ridge and westward to the Chersky Range in eastern Siberia. The plate includes both continental and oceanic crust. The interior of the main continental landmass includes an extensive granitic core called a craton. Along most of the edges of this craton are fragments of crustal material called terranes, which are accreted to the craton by tectonic actions over a long span of time. It is thought that much of North America west of the Rocky Mountains is composed of such terranes. Boundaries The southern boundary with the Cocos Plate to the west and the Caribbean Plate to the east is a transform fault, represented by the Swan Islands Transform Fault unde ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
