document_title: Earthquake

question_text: where does most seismic activity occur on earth

question_tokens: where does most seismic activity occur on earth

text: Earthquake

text: Naturally occurring earthquakes

text: Tectonic earthquakes occur anywhere in the earth where there is sufficient stored elastic strain energy to drive fracture propagation along a fault plane. 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. Most fault surfaces do have such asperities and this leads to a form of stick-slip behavior. Once the fault has locked, continued relative motion between the plates leads to increasing stress and therefore, stored strain energy in the volume around the fault surface. This continues until the stress has risen sufficiently to break through the asperity, suddenly allowing sliding over the locked portion of the fault, releasing the stored energy.[1] This energy is released as a combination of radiated elastic strain seismic waves, frictional heating of the fault surface, and cracking of the rock, thus causing an earthquake. This process of gradual build-up of strain and stress punctuated by occasional sudden earthquake failure is referred to as the elastic-rebound theory. It is estimated that only 10 percent or less of an earthquake's total energy is radiated as seismic energy. Most of the earthquake's energy is used to power the earthquake fracture growth or is converted into heat generated by friction. Therefore, earthquakes lower the Earth's available elastic potential energy and raise its temperature, though these changes are negligible compared to the conductive and convective flow of heat out from the Earth's deep interior.[2]

text: Earthquake fault types

text: There are three main types of fault, all of which may cause an interplate earthquake: normal, reverse (thrust) and strike-slip. Normal and reverse faulting are examples of dip-slip, where the displacement along the fault is in the direction of dip and movement on them involves a vertical component. Normal faults occur mainly in areas where the crust is being extended such as a divergent boundary. Reverse faults occur in areas where the crust is being shortened such as at a convergent boundary. Strike-slip faults are steep structures where the two sides of the fault slip horizontally past each other; transform boundaries are a particular type of strike-slip fault. Many earthquakes are caused by movement on faults that have components of both dip-slip and strike-slip; this is known as oblique slip.

text: 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. Strike-slip faults, particularly continental transforms, can produce major earthquakes up to about magnitude 8. Earthquakes associated with normal faults are generally less than magnitude 7. For every unit increase in magnitude, there is a roughly thirtyfold increase in the energy released. For instance, an earthquake of magnitude 6.0 releases approximately 30 times more energy than a 5.0 magnitude earthquake and a 7.0 magnitude earthquake releases 900 times (30 × 30) more energy than a 5.0 magnitude of earthquake. An 8.6 magnitude earthquake releases the same amount of energy as 10,000 atomic bombs like those used in World War II.[3]

text: This is so because the energy released in an earthquake, and thus its magnitude, is proportional to the area of the fault that ruptures[4] and the stress drop. Therefore, the longer the length and the wider the width of the faulted area, the larger the resulting magnitude. The topmost, brittle part of the Earth's crust, and the cool slabs of the tectonic plates that are descending down into the hot mantle, are the only parts of our planet which can store elastic energy and release it in fault ruptures. Rocks hotter than about 300 degrees Celsius flow in response to stress; they do not rupture in earthquakes.[5][6] The maximum observed lengths of ruptures and mapped faults (which may break in a single rupture) are approximately 1000 km. Examples are the earthquakes in Chile, 1960; Alaska, 1957; Sumatra, 2004, all in subduction zones. The longest earthquake ruptures on strike-slip faults, like the San Andreas Fault (1857, 1906), the North Anatolian Fault in Turkey (1939) and the Denali Fault in Alaska (2002), are about half to one third as long as the lengths along subducting plate margins, and those along normal faults are even shorter.

text: The most important parameter controlling the maximum earthquake magnitude on a fault is however not the maximum available length, but the available width because the latter varies by a factor of 20. Along converging plate margins, the dip angle of the rupture plane is very shallow, typically about 10 degrees.[7] Thus the width of the plane within the top brittle crust of the Earth can become 50 to 100 km (Japan, 2011; Alaska, 1964), making the most powerful earthquakes possible.

text: Strike-slip faults tend to be oriented near vertically, resulting in an approximate width of 10 km within the brittle crust,[8] thus earthquakes with magnitudes much larger than 8 are not possible. Maximum magnitudes along many normal faults are even more limited because many of them are located along spreading centers, as in Iceland, where the thickness of the brittle layer is only about 6 km.[9][10]

text: In addition, there exists a hierarchy of stress level in the three fault types. Thrust faults are generated by the highest, strike slip by intermediate, and normal faults by the lowest stress levels.[11] This can easily be understood by considering the direction of the greatest principal stress, the direction of the force that 'pushes' the rock mass during the faulting. In the case of normal faults, the rock mass is pushed down in a vertical direction, thus the pushing force (greatest principal stress) equals the weight of the rock mass itself. In the case of thrusting, the rock mass 'escapes' in the direction of the least principal stress, namely upward, lifting the rock mass up, thus the overburden equals the least principal stress. Strike-slip faulting is intermediate between the other two types described above. This difference in stress regime in the three faulting environments can contribute to differences in stress drop during faulting, which contributes to differences in the radiated energy, regardless of fault dimensions.

text: Earthquakes away from plate boundaries

text: Where plate boundaries occur within the continental lithosphere, deformation is spread out over a much larger area than the plate boundary itself. In the case of the San Andreas fault continental transform, many earthquakes occur away from the plate boundary and are related to strains developed within the broader zone of deformation caused by major irregularities in the fault trace (e.g., the "Big bend" region). The Northridge earthquake was associated with movement on a blind thrust within such a zone. Another example is the strongly oblique convergent plate boundary between the Arabian and Eurasian plates where it runs through the northwestern part of the Zagros Mountains. The deformation associated with this plate boundary is partitioned into nearly pure thrust sense movements perpendicular to the boundary over a wide zone to the southwest and nearly pure strike-slip motion along the Main Recent Fault close to the actual plate boundary itself. This is demonstrated by earthquake focal mechanisms.[12]

text: All tectonic plates have internal stress fields caused by their interactions with neighboring plates and sedimentary loading or unloading (e.g. deglaciation).[13] These stresses may be sufficient to cause failure along existing fault planes, giving rise to intraplate earthquakes.[14]

text: Shallow-focus and deep-focus earthquakes

text: The majority of tectonic earthquakes originate at the ring of fire in depths not exceeding tens of kilometers. Earthquakes occurring at a depth of less than 70 km are classified as 'shallow-focus' earthquakes, while those with a focal-depth between 70 and 300 km are commonly termed 'mid-focus' or 'intermediate-depth' earthquakes. 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 300 up to 700 kilometers).[15] These seismically active areas of subduction are known as Wadati–Benioff zones. Deep-focus earthquakes occur at a depth where the subducted lithosphere should no longer be brittle, due to the high temperature and pressure. A possible mechanism for the generation of deep-focus earthquakes is faulting caused by olivine undergoing a phase transition into a spinel structure.[16]

text: Earthquakes and volcanic activity

text: Earthquakes often occur in volcanic regions and are caused there, both by tectonic faults and the movement of magma in volcanoes. Such earthquakes can serve as an early warning of volcanic eruptions, as during the 1980 eruption of Mount St. Helens.[17] Earthquake swarms can serve as markers for the location of the flowing magma throughout the volcanoes. These swarms can be recorded by seismometers and tiltmeters (a device that measures ground slope) and used as sensors to predict imminent or upcoming eruptions.[18]

text: Rupture dynamics

text: A tectonic earthquake begins by an initial rupture at a point on the fault surface, a process known as nucleation. The scale of the nucleation zone is uncertain, with some evidence, such as the rupture dimensions of the smallest earthquakes, suggesting that it is smaller than 100 m while other evidence, such as a slow component revealed by low-frequency spectra of some earthquakes, suggest that it is larger. The possibility that the nucleation involves some sort of preparation process is supported by the observation that about 40% of earthquakes are preceded by foreshocks. Once the rupture has initiated, it begins to propagate along the fault surface. The mechanics of this process are poorly understood, partly because it is difficult to recreate the high sliding velocities in a laboratory. Also the effects of strong ground motion make it very difficult to record information close to a nucleation zone.[19]

text: Rupture propagation is generally modeled using a fracture mechanics approach, likening the rupture to a propagating mixed mode shear crack. The rupture velocity is a function of the fracture energy in the volume around the crack tip, increasing with decreasing fracture energy. The velocity of rupture propagation is orders of magnitude faster than the displacement velocity across the fault. Earthquake ruptures typically propagate at velocities that are in the range 70–90% of the S-wave velocity, and this is independent of earthquake size. A small subset of earthquake ruptures appear to have propagated at speeds greater than the S-wave velocity. These supershear earthquakes have all been observed during large strike-slip events. The unusually wide zone of coseismic damage caused by the 2001 Kunlun earthquake has been attributed to the effects of the sonic boom developed in such earthquakes. Some earthquake ruptures travel at unusually low velocities and are referred to as slow earthquakes. 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.[19]

text: Tidal forces

text: Tides may induce some seismicity, see tidal triggering of earthquakes for details.

text: Earthquake clusters

text: Most earthquakes form part of a sequence, related to each other in terms of location and time.[20] Most earthquake clusters consist of small tremors that cause little to no damage, but there is a theory that earthquakes can recur in a regular pattern.[21]

text: Aftershocks

text: An aftershock is an earthquake that occurs after a previous earthquake, the mainshock. An aftershock is in the same region of the main shock but always of a smaller magnitude. 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. Aftershocks are formed as the crust around the displaced fault plane adjusts to the effects of the main shock.[20]

text: Earthquake swarms

text: Earthquake swarms are sequences of earthquakes striking in a specific area within a short period of time. 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 example of an earthquake swarm is the 2004 activity at Yellowstone National Park.[22] In August 2012, a swarm of earthquakes shook Southern California's Imperial Valley, showing the most recorded activity in the area since the 1970s.[23]

text: Sometimes a series of earthquakes occur in what has been called an earthquake storm, where the earthquakes strike a fault in clusters, each triggered by the shaking or stress redistribution of the previous earthquakes. Similar to aftershocks but on adjacent segments of fault, these storms occur over the course of years, and with some of the later earthquakes as damaging as the early ones. Such a pattern was observed in the sequence of about a dozen earthquakes that struck the North Anatolian Fault in Turkey in the 20th century and has been inferred for older anomalous clusters of large earthquakes in the Middle East.[24][25]

text: Intensity of earth quaking and magnitude of earthquakes

text: Quaking or shaking of the earth is a common phenomenon undoubtedly known to humans from earliest times. 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. Only in the last century has the source of such shaking been identified as ruptures in the earth's crust, with the intensity of shaking at any locality dependent not only on the local ground conditions, but also on the strength or magnitude of the rupture, and on its distance.[26]

text: The first scale for measuring earthquake magnitudes was developed by Charles F. Richter in 1935. Subsequent scales (see seismic magnitude scales) have retained a key feature, where each unit represents a ten-fold difference in the amplitude of the ground shaking, and a 32-fold difference in energy. Subsequent scales are also adjusted to have approximately the same numeric value within the limits of the scale.[27]

text: Although the mass media commonly reports earthquake magnitudes as "Richter magnitude" or "Richter scale", standard practice by most seismological authorities is to express an earthquake's strength on the moment magnitude scale, which is based on the actual energy released by an earthquake.[28]

text: Frequency of occurrence

text: It is estimated that around 500,000 earthquakes occur each year, detectable with current instrumentation. About 100,000 of these can be felt.[29][30] Minor earthquakes occur nearly constantly around the world in places like California and Alaska in the U.S., as well as in El Salvador, Mexico, Guatemala, Chile, Peru, Indonesia, Iran, Pakistan, the Azores in Portugal, Turkey, New Zealand, Greece, Italy, India, Nepal and Japan, but earthquakes can occur almost anywhere, including Downstate New York, England, and Australia.[31] Larger earthquakes occur less frequently, the relationship being exponential; for example, roughly ten times as many earthquakes larger than magnitude 4 occur in a particular time period than earthquakes larger than magnitude 5.[32] In the (low seismicity) United Kingdom, for example, it has been calculated that the average recurrences are: an earthquake of 3.7–4.6 every year, an earthquake of 4.7–5.5 every 10 years, and an earthquake of 5.6 or larger every 100 years.[33] This is an example of the Gutenberg–Richter law.

text: The number of seismic stations has increased from about 350 in 1931 to many thousands today. As a result, many more earthquakes are reported than in the past, but this is because of the vast improvement in instrumentation, rather than an increase in the number of earthquakes. The United States Geological Survey estimates that, since 1900, there have been an average of 18 major earthquakes (magnitude 7.0–7.9) and one great earthquake (magnitude 8.0 or greater) per year, and that this average has been relatively stable.[35] In recent years, the number of major earthquakes per year has decreased, though this is probably a statistical fluctuation rather than a systematic trend.[36] More detailed statistics on the size and frequency of earthquakes is available from the United States Geological Survey (USGS).[37] A recent increase in the number of major earthquakes has been noted, which could be explained by a cyclical pattern of periods of intense tectonic activity, interspersed with longer periods of low-intensity. However, accurate recordings of earthquakes only began in the early 1900s, so it is too early to categorically state that this is the case.[38]

text: Most of the world's earthquakes (90%, and 81% of the largest) take place in the 40,000 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.[39][40] Massive earthquakes tend to occur along other plate boundaries, too, such as along the Himalayan Mountains.[41]

text: With the rapid growth of mega-cities such as Mexico City, Tokyo and Tehran, in areas of high seismic risk, some seismologists are warning that a single quake may claim the lives of up to 3 million people.[42]

text: Induced seismicity

text: While most earthquakes are caused by movement of the Earth's tectonic plates, human activity can also produce earthquakes. Four main activities contribute to this phenomenon: storing large amounts of water behind a dam (and possibly building an extremely heavy building), drilling and injecting liquid into wells, and by coal mining and oil drilling.[43] Perhaps the best known example is the 2008 Sichuan earthquake in China's Sichuan Province in May; this tremor resulted in 69,227 fatalities and is the 19th deadliest earthquake of all time. The Zipingpu Dam is believed to have fluctuated the pressure of the fault 1,650 feet (503 m) away; this pressure probably increased the power of the earthquake and accelerated the rate of movement for the fault.[44] The greatest earthquake in Australia's history is also claimed to be induced by humanity, through coal mining. The city of Newcastle was built over a large sector of coal mining areas. The earthquake has been reported to be spawned from a fault that reactivated due to the millions of tonnes of rock removed in the mining process.[45]

text: Measuring and locating earthquakes

text: The instrumental scales used to describe the size of an earthquake began with the Richter magnitude scale in the 1930s. It is a relatively simple measurement of an event's amplitude, and its use has become minimal in the 21st century. Seismic waves travel through the Earth's interior and can be recorded by seismometers at great distances. The surface wave magnitude was developed in the 1950s as a means to measure remote earthquakes and to improve the accuracy for larger events. The moment magnitude scale measures the amplitude of the shock, but also takes into account the seismic moment (total rupture area, average slip of the fault, and rigidity of the rock). The Japan Meteorological Agency seismic intensity scale, the Medvedev–Sponheuer–Karnik scale, and the Mercalli intensity scale are based on the observed effects and are related to the intensity of shaking.

text: Every tremor produces different types of seismic waves, which travel through rock with different velocities:

text:
Longitudinal P-waves (shock- or pressure waves)
Transverse S-waves (both body waves)
Surface waves — (Rayleigh and Love waves)

text: Propagation velocity of the seismic waves ranges from approx. 3 km/s up to 13 km/s, depending on the density and elasticity of the medium. In the Earth's interior the shock- or P waves travel much faster than the S waves (approx. relation 1.7 : 1). The differences in travel time from the epicenter to the observatory are a measure of the distance and can be used to image both sources of quakes and structures within the Earth. Also, the depth of the hypocenter can be computed roughly.

text: In solid rock P-waves travel at about 6 to 7 km per second; the velocity increases within the deep mantle to ~13 km/s. The velocity of S-waves ranges from 2–3 km/s in light sediments and 4–5 km/s in the Earth's crust up to 7 km/s in the deep mantle. As a consequence, the first waves of a distant earthquake arrive at an observatory via the Earth's mantle.

text: On average, the kilometer distance to the earthquake is the number of seconds between the P and S wave times 8.[46] Slight deviations are caused by inhomogeneities of subsurface structure. By such analyses of seismograms the Earth's core was located in 1913 by Beno Gutenberg.

text: S waves and later arriving surface waves do main damage compared to P waves. P wave squeezes and expands material in the same direction it is traveling. S wave shakes the ground up and down and back and forth.[47]

text: Earthquakes are not only categorized by their magnitude but also by the place where they occur. The world is divided into 754 Flinn–Engdahl regions (F-E regions), which are based on political and geographical boundaries as well as seismic activity. More active zones are divided into smaller F-E regions whereas less active zones belong to larger F-E regions.

text: Standard reporting of earthquakes includes its magnitude, date and time of occurrence, geographic coordinates of its epicenter, depth of the epicenter, geographical region, distances to population centers, location uncertainty, a number of parameters that are included in USGS earthquake reports (number of stations reporting, number of observations, etc.), and a unique event ID.[48]

text: Although relatively slow seismic waves have traditionally been used to detect earthquakes, scientists realized in 2016 that gravitational measurements could provide instantaneous detection of earthquakes, and confirmed this by analyzing gravitational records associated with the 2011 Tohoku-Oki ("Fukushima") earthquake.[49][50]

text: Effects of earthquakes

text: The effects of earthquakes include, but are not limited to, the following:

text: Shaking and ground rupture

text: Shaking and ground rupture are the main effects created by earthquakes, principally resulting in more or less severe damage to buildings and other rigid structures. The severity of the local effects depends on the complex combination of the earthquake magnitude, the distance from the epicenter, and the local geological and geomorphological conditions, which may amplify or reduce wave propagation.[51] The ground-shaking is measured by ground acceleration.

text: Specific local geological, geomorphological, and geostructural features can induce high levels of shaking on the ground surface even from low-intensity earthquakes. This effect is called site or local amplification. It is principally due to the transfer of the seismic motion from hard deep soils to soft superficial soils and to effects of seismic energy focalization owing to typical geometrical setting of the deposits.

text: Ground rupture is a visible breaking and displacement of the Earth's surface along the trace of the fault, which may be of the order of several meters in the case of major earthquakes. Ground rupture is a major risk for large engineering structures such as dams, bridges and nuclear power stations and requires careful mapping of existing faults to identify any which are likely to break the ground surface within the life of the structure.[52]

text: Landslides and avalanches

text: Earthquakes, along with severe storms, volcanic activity, coastal wave attack, and wildfires, can produce slope instability leading to landslides, a major geological hazard. Landslide danger may persist while emergency personnel are attempting rescue.[53]

text: Fires

text: Earthquakes can cause fires by damaging electrical power or gas lines. In the event of water mains rupturing and a loss of pressure, it may also become difficult to stop the spread of a fire once it has started. For example, more deaths in the 1906 San Francisco earthquake were caused by fire than by the earthquake itself.[54]

text: Soil liquefaction

text: Soil liquefaction occurs when, because of the shaking, water-saturated granular material (such as sand) temporarily loses its strength and transforms from a solid to a liquid. Soil liquefaction may cause rigid structures, like buildings and bridges, to tilt or sink into the liquefied deposits. For example, in the 1964 Alaska earthquake, soil liquefaction caused many buildings to sink into the ground, eventually collapsing upon themselves.[55]

text: Tsunami

text: Tsunamis are long-wavelength, long-period sea waves produced by the sudden or abrupt movement of large volumes of water – including when an earthquake occurs at sea. In the open ocean the distance between wave crests can surpass 100 kilometers (62 mi), and the wave periods can vary from five minutes to one hour. Such tsunamis travel 600–800 kilometers per hour (373–497 miles per hour), depending on water depth. Large waves produced by an earthquake or a submarine landslide can overrun nearby coastal areas in a matter of minutes. Tsunamis can also travel thousands of kilometers across open ocean and wreak destruction on far shores hours after the earthquake that generated them.[56]

text: Ordinarily, subduction earthquakes under magnitude 7.5 on the Richter magnitude scale do not cause tsunamis, although some instances of this have been recorded. Most destructive tsunamis are caused by earthquakes of magnitude 7.5 or more.[56]

text: Floods

text: A flood is an overflow of any amount of water that reaches land.[57] Floods occur usually when the volume of water within a body of water, such as a river or lake, exceeds the total capacity of the formation, and as a result some of the water flows or sits outside of the normal perimeter of the body. However, floods may be secondary effects of earthquakes, if dams are damaged. Earthquakes may cause landslips to dam rivers, which collapse and cause floods.[58]

text: The terrain below the Sarez Lake in Tajikistan is in danger of catastrophic flood if the landslide dam formed by the earthquake, known as the Usoi Dam, were to fail during a future earthquake. Impact projections suggest the flood could affect roughly 5 million people.[59]

text: Human impacts

text: An earthquake may cause injury and loss of life, road and bridge damage, general property damage, and collapse or destabilization (potentially leading to future collapse) of buildings. The aftermath may bring disease, lack of basic necessities, mental consequences such as panic attacks, depression to survivors,[60] and higher insurance premiums.

text: Major earthquakes

text: One of the most devastating earthquakes in recorded history was the 1556 Shaanxi earthquake, which occurred on 23 January 1556 in Shaanxi province, China. More than 830,000 people died.[62] Most houses in the area were yaodongs—dwellings carved out of loess hillsides—and many victims were killed when these structures collapsed. The 1976 Tangshan earthquake, which killed between 240,000 and 655,000 people, was the deadliest of the 20th century.[63]

text: The 1960 Chilean earthquake is the largest earthquake that has been measured on a seismograph, reaching 9.5 magnitude on 22 May 1960.[29][30] Its epicenter was near Cañete, Chile. The energy released was approximately twice that of the next most powerful earthquake, the Good Friday earthquake (March 27, 1964) which was centered in Prince William Sound, Alaska.[64][65] The ten largest recorded earthquakes have all been megathrust earthquakes; however, of these ten, only the 2004 Indian Ocean earthquake is simultaneously one of the deadliest earthquakes in history.

text: Earthquakes that caused the greatest loss of life, while powerful, were deadly because of their proximity to either heavily populated areas or the ocean, where earthquakes often create tsunamis that can devastate communities thousands of kilometers away. Regions most at risk for great loss of life include those where earthquakes are relatively rare but powerful, and poor regions with lax, unenforced, or nonexistent seismic building codes.

text: Prediction

text: Earthquake prediction is a branch of the science of seismology concerned with the specification of the time, location, and magnitude of future earthquakes within stated limits.[66] Many methods have been developed for predicting the time and place in which earthquakes will occur. Despite considerable research efforts by seismologists, scientifically reproducible predictions cannot yet be made to a specific day or month.[67]

text: Forecasting

text: While forecasting is usually considered to be a type of prediction, earthquake forecasting is often differentiated from earthquake prediction. Earthquake forecasting is concerned with the probabilistic assessment of general earthquake hazard, including the frequency and magnitude of damaging earthquakes in a given area over years or decades.[68] For well-understood faults the probability that a segment may rupture during the next few decades can be estimated.[69][70]

text: Earthquake warning systems have been developed that can provide regional notification of an earthquake in progress, but before the ground surface has begun to move, potentially allowing people within the system's range to seek shelter before the earthquake's impact is felt.

text: Preparedness

text: The objective of earthquake engineering is to foresee the impact of earthquakes on buildings and other structures and to design such structures to minimize the risk of damage. Existing structures can be modified by seismic retrofitting to improve their resistance to earthquakes. Earthquake insurance can provide building owners with financial protection against losses resulting from earthquakes.

text: Emergency management strategies can be employed by a government or organization to mitigate risks and prepare for consequences.

text: Historical views

text: From the lifetime of the Greek philosopher Anaxagoras in the 5th century BCE to the 14th century CE, earthquakes were usually attributed to "air (vapors) in the cavities of the Earth."[71] Thales of Miletus, who lived from 625–547 (BCE) was the only documented person who believed that earthquakes were caused by tension between the earth and water.[71] Other theories existed, including the Greek philosopher Anaxamines' (585–526 BCE) beliefs that short incline episodes of dryness and wetness caused seismic activity. The Greek philosopher Democritus (460–371 BCE) blamed water in general for earthquakes.[71] Pliny the Elder called earthquakes "underground thunderstorms."[71]

text: Recent studies

text: In recent studies, geologists claim that global warming is one of the reasons for increased seismic activity. According to these studies melting glaciers and rising sea levels disturb the balance of pressure on Earth's tectonic plates thus causing increase in the frequency and intensity of earthquakes.[72]

text: In culture

text: Mythology and religion

text: In Norse mythology, earthquakes were explained as the violent struggling of the god Loki. When Loki, god of mischief and strife, murdered Baldr, god of beauty and light, he was punished by being bound in a cave with a poisonous serpent placed above his head dripping venom. Loki's wife Sigyn stood by him with a bowl to catch the poison, but whenever she had to empty the bowl the poison dripped on Loki's face, forcing him to jerk his head away and thrash against his bonds, which caused the earth to tremble.[73]

text: In Greek mythology, Poseidon was the cause and god of earthquakes. When he was in a bad mood, he struck the ground with a trident, causing earthquakes and other calamities. He also used earthquakes to punish and inflict fear upon people as revenge.[74]

text: In Japanese mythology, Namazu (鯰) is a giant catfish who causes earthquakes. Namazu lives in the mud beneath the earth, and is guarded by the god Kashima who restrains the fish with a stone. When Kashima lets his guard fall, Namazu thrashes about, causing violent earthquakes.[75]

text: In popular culture

text: In modern popular culture, the portrayal of earthquakes is shaped by the memory of great cities laid waste, such as Kobe in 1995 or San Francisco in 1906.[76] Fictional earthquakes tend to strike suddenly and without warning.[76] For this reason, stories about earthquakes generally begin with the disaster and focus on its immediate aftermath, as in Short Walk to Daylight (1972), The Ragged Edge (1968) or Aftershock: Earthquake in New York (1999).[76] A notable example is Heinrich von Kleist's classic novella, The Earthquake in Chile, which describes the destruction of Santiago in 1647. Haruki Murakami's short fiction collection After the Quake depicts the consequences of the Kobe earthquake of 1995.

text: The most popular single earthquake in fiction is the hypothetical "Big One" expected of California's San Andreas Fault someday, as depicted in the novels Richter 10 (1996), Goodbye California (1977), 2012 (2009) and San Andreas (2015) among other works.[76] Jacob M. Appel's widely anthologized short story, A Comparative Seismology, features a con artist who convinces an elderly woman that an apocalyptic earthquake is imminent.[77]

text: Contemporary depictions of earthquakes in film are variable in the manner in which they reflect human psychological reactions to the actual trauma that can be caused to directly afflicted families and their loved ones.[78] Disaster mental health response research emphasizes the need to be aware of the different roles of loss of family and key community members, loss of home and familiar surroundings, loss of essential supplies and services to maintain survival.[79][80] Particularly for children, the clear availability of caregiving adults who are able to protect, nourish, and clothe them in the aftermath of the earthquake, and to help them make sense of what has befallen them has been shown even more important to their emotional and physical health than the simple giving of provisions.[81] As was observed after other disasters involving destruction and loss of life and their media depictions, recently observed in the 2010 Haiti earthquake, it is also important not to pathologize the reactions to loss and displacement or disruption of governmental administration and services, but rather to validate these reactions, to support constructive problem-solving and reflection as to how one might improve the conditions of those affected.[82]


document_title: Banana

question_text: when were bananas introduced to the united states

question_tokens: when were bananas introduced to the united states

root

text: Banana

text: Description

text: The banana plant is the largest herbaceous flowering plant.[7] All the above-ground parts of a banana plant grow from a structure usually called a "corm".[8] Plants are normally tall and fairly sturdy, and are often mistaken for trees, but what appears to be a trunk is actually a "false stem" or pseudostem. Bananas grow in a wide variety of soils, as long as the soil is at least 60 cm deep, has good drainage and is not compacted.[9] The leaves of banana plants are composed of a "stalk" (petiole) and a blade (lamina). The base of the petiole widens to form a sheath; the tightly packed sheaths make up the pseudostem, which is all that supports the plant. The edges of the sheath meet when it is first produced, making it tubular. As new growth occurs in the centre of the pseudostem the edges are forced apart.[10] Cultivated banana plants vary in height depending on the variety and growing conditions. Most are around 5 m (16 ft) tall, with a range from 'Dwarf Cavendish' plants at around 3 m (10 ft) to 'Gros Michel' at 7 m (23 ft) or more.[11][12] Leaves are spirally arranged and may grow 2.7 metres (8.9 ft) long and 60 cm (2.0 ft) wide.[1] They are easily torn by the wind, resulting in the familiar frond look.[13]

tag: p

text: When a banana plant is mature, the corm stops producing new leaves and begins to form a flower spike or inflorescence. A stem develops which grows up inside the pseudostem, carrying the immature inflorescence until eventually it emerges at the top.[14] Each pseudostem normally produces a single inflorescence, also known as the "banana heart". (More are sometimes produced; an exceptional plant in the Philippines produced five.[15]) After fruiting, the pseudostem dies, but offshoots will normally have developed from the base, so that the plant as a whole is perennial. In the plantation system of cultivation, only one of the offshoots will be allowed to develop in order to maintain spacing.[16] The inflorescence contains many bracts (sometimes incorrectly referred to as petals) between rows of flowers. The female flowers (which can develop into fruit) appear in rows further up the stem (closer to the leaves) from the rows of male flowers. The ovary is inferior, meaning that the tiny petals and other flower parts appear at the tip of the ovary.[17]

text: The banana fruits develop from the banana heart, in a large hanging cluster, made up of tiers (called "hands"), with up to 20 fruit to a tier. The hanging cluster is known as a bunch, comprising 3–20 tiers, or commercially as a "banana stem", and can weigh 30–50 kilograms (66–110 lb). Individual banana fruits (commonly known as a banana or "finger") average 125 grams (0.276 lb), of which approximately 75% is water and 25% dry matter (nutrient table, lower right).

text: The fruit has been described as a "leathery berry".[18] There is a protective outer layer (a peel or skin) with numerous long, thin strings (the phloem bundles), which run lengthwise between the skin and the edible inner portion. The inner part of the common yellow dessert variety can be split lengthwise into three sections that correspond to the inner portions of the three carpels by manually deforming the unopened fruit.[19] In cultivated varieties, the seeds are diminished nearly to non-existence; their remnants are tiny black specks in the interior of the fruit.[20]

text: Bananas are naturally slightly radioactive,[21] more so than most other fruits, because of their potassium content and the small amounts of the isotope potassium-40 found in naturally occurring potassium.[22] The banana equivalent dose of radiation is sometimes used in nuclear communication to compare radiation levels and exposures.[23]

text: Etymology

text: The word banana is thought to be of West African origin, possibly from the Wolof word banaana, and passed into English via Spanish or Portuguese.[24]

text: Taxonomy

text: The genus Musa was created by Carl Linnaeus in 1753.[25] The name may be derived from Antonius Musa, physician to the Emperor Augustus, or Linnaeus may have adapted the Arabic word for banana, mauz.[26] The old biological name Musa sapientum = "Muse of the wise" arose because of homophony in Latin with the classical Muses.

text: Musa is in the family Musaceae. The APG III system assigns Musaceae to the order Zingiberales, part of the commelinid clade of the monocotyledonous flowering plants. Some 70 species of Musa were recognized by the World Checklist of Selected Plant Families as of January 2013[update];[25] several produce edible fruit, while others are cultivated as ornamentals.[27]

text: The classification of cultivated bananas has long been a problematic issue for taxonomists. Linnaeus originally placed bananas into two species based only on their uses as food: Musa sapientum for dessert bananas and Musa paradisiaca for plantains. More species names were added, but this approach proved to be inadequate for the number of cultivars in the primary center of diversity of the genus, Southeast Asia. Many of these cultivars were given names that were later discovered to be synonyms.[28]

text: In a series of papers published from 1947 onwards, Ernest Cheesman showed that Linnaeus's Musa sapientum and Musa paradisiaca were cultivars and descendants of two wild seed-producing species, Musa acuminata and Musa balbisiana, both first described by Luigi Aloysius Colla.[29] Cheesman recommended the abolition of Linnaeus's species in favor of reclassifying bananas according to three morphologically distinct groups of cultivars – those primarily exhibiting the botanical characteristics of Musa balbisiana, those primarily exhibiting the botanical characteristics of Musa acuminata, and those with characteristics of both.[28] Researchers Norman Simmonds and Ken Shepherd proposed a genome-based nomenclature system in 1955. This system eliminated almost all the difficulties and inconsistencies of the earlier classification of bananas based on assigning scientific names to cultivated varieties. Despite this, the original names are still recognized by some authorities today, leading to confusion.[29][30]

text: The accepted scientific names for most groups of cultivated bananas are Musa acuminata Colla and Musa balbisiana Colla for the ancestral species, and Musa × paradisiaca L. for the hybrid M. acuminata × M. balbisiana.[31]

text: Synonyms of M. × paradisica include

text:
a large number of subspecific and varietial names of M. × paradisiaca, including M. p. subsp. sapientum (L.) Kuntze
Musa × dacca Horan.
Musa × sapidisiaca K.C.Jacob, nom. superfl.
Musa × sapientum L., and a large number of its varietal names, including M. × sapientum var. paradisiaca (L.) Baker, nom. illeg.

tag: ul

text: Generally, modern classifications of banana cultivars follow Simmonds and Shepherd's system. Cultivars are placed in groups based on the number of chromosomes they have and which species they are derived from. Thus the Latundan banana is placed in the AAB Group, showing that it is a triploid derived from both M. acuminata (A) and M. balbisiana (B). For a list of the cultivars classified under this system, see "List of banana cultivars".

text: In 2012, a team of scientists announced they had achieved a draft sequence of the genome of Musa acuminata.[32]

text: Bananas and plantains

text: In regions such as North America and Europe, Musa fruits offered for sale can be divided into "bananas" and "plantains", based on their intended use as food. Thus the banana producer and distributor Chiquita produces publicity material for the American market which says that "a plantain is not a banana". The stated differences are that plantains are more starchy and less sweet; they are eaten cooked rather than raw; they have thicker skin, which may be green, yellow or black; and they can be used at any stage of ripeness.[33] Linnaeus made the same distinction between plantains and bananas when first naming two "species" of Musa.[34] Members of the "plantain subgroup" of banana cultivars, most important as food in West Africa and Latin America, correspond to the Chiquita description, having long pointed fruit. They are described by Ploetz et al. as "true" plantains, distinct from other cooking bananas.[35] The cooking bananas of East Africa belong to a different group, the East African Highland bananas,[12] so would not qualify as "true" plantains on this definition.

text: An alternative approach divides bananas into dessert bananas and cooking bananas, with plantains being one of the subgroups of cooking bananas.[36] Triploid cultivars derived solely from M. acuminata are examples of "dessert bananas", whereas triploid cultivars derived from the hybrid between M. acuminata and M. balbinosa (in particular the plantain subgroup of the AAB Group) are "plantains".[37][38] Small farmers in Colombia grow a much wider range of cultivars than large commercial plantations. A study of these cultivars showed that they could be placed into at least three groups based on their characteristics: dessert bananas, non-plantain cooking bananas, and plantains, although there were overlaps between dessert and cooking bananas.[39]

text: In Southeast Asia – the center of diversity for bananas, both wild and cultivated – the distinction between "bananas" and "plantains" does not work, according to Valmayor et al. Many bananas are used both raw and cooked. There are starchy cooking bananas which are smaller than those eaten raw. The range of colors, sizes and shapes is far wider than in those grown or sold in Africa, Europe or the Americas.[34] Southeast Asian languages do not make the distinction between "bananas" and "plantains" that is made in English (and Spanish). Thus both Cavendish cultivars, the classic yellow dessert bananas, and Saba cultivars, used mainly for cooking, are called pisang in Malaysia and Indonesia, kluai in Thailand and chuoi in Vietnam.[40] Fe'i bananas, grown and eaten in the islands of the Pacific, are derived from entirely different wild species than traditional bananas and plantains. Most Fe'i bananas are cooked, but Karat bananas, which are short and squat with bright red skins, very different from the usual yellow dessert bananas, are eaten raw.[41]

text: In summary, in commerce in Europe and the Americas (although not in small-scale cultivation), it is possible to distinguish between "bananas", which are eaten raw, and "plantains", which are cooked. In other regions of the world, particularly India, Southeast Asia and the islands of the Pacific, there are many more kinds of banana and the two-fold distinction is not useful and not made in local languages. Plantains are one of many kinds of cooking bananas, which are not always distinct from dessert bananas.

text: Historical cultivation

text: Early cultivation

text: Farmers in Southeast Asia and Papua New Guinea first domesticated bananas. Recent archaeological and palaeoenvironmental evidence at Kuk Swamp in the Western Highlands Province of Papua New Guinea suggests that banana cultivation there goes back to at least 5000 BCE, and possibly to 8000 BCE.[4][43] It is likely that other species were later and independently domesticated elsewhere in Southeast Asia. Southeast Asia is the region of primary diversity of the banana. Areas of secondary diversity are found in Africa, indicating a long history of banana cultivation in the region.[44]

text: Phytolith discoveries in Cameroon dating to the first millennium BCE[46] triggered an as yet unresolved debate about the date of first cultivation in Africa. There is linguistic evidence that bananas were known in Madagascar around that time.[47] The earliest prior evidence indicates that cultivation dates to no earlier than late 6th century CE.[48] It is likely, however, that bananas were brought at least to Madagascar if not to the East African coast during the phase of Malagasy colonization of the island from South East Asia c. 400 CE.[49]

text: The banana may also have been present in isolated locations elsewhere in the Middle East on the eve of Islam. The spread of Islam was followed by far-reaching diffusion. There are numerous references to it in Islamic texts (such as poems and hadiths) beginning in the 9th century. By the 10th century the banana appears in texts from Palestine and Egypt. From there it diffused into North Africa and Muslim Iberia. During the medieval ages, bananas from Granada were considered among the best in the Arab world.[45] In 650, Islamic conquerors brought the banana to Palestine. Today, banana consumption increases significantly in Islamic countries during Ramadan, the month of daylight fasting.[50]

text: Bananas were certainly grown in the Christian Kingdom of Cyprus by the late medieval period. Writing in 1458, the Italian traveller and writer Gabriele Capodilista wrote favourably of the extensive farm produce of the estates at Episkopi, near modern-day Limassol, including the region's banana plantations.[51]

text: Bananas were introduced to the Americas by Portuguese sailors who brought the fruits from West Africa in the 16th century.[52]

text: Many wild banana species as well as cultivars exist in extraordinary diversity in India, China, and Southeast Asia.

text: There are fuzzy bananas whose skins are bubblegum pink; green-and-white striped bananas with pulp the color of orange sherbet; bananas that, when cooked, taste like strawberries. The Double Mahoi plant can produce two bunches at once. The Chinese name of the aromatic Go San Heong banana means 'You can smell it from the next mountain.' The fingers on one banana plant grow fused; another produces bunches of a thousand fingers, each only an inch long.

text: In 1999, archaeologists in London discovered what they believed to be the oldest banana in the UK, in a Tudor rubbish tip.[54]

text: Plantation cultivation in the Caribbean, Central and South America

text: In the 15th and 16th centuries, Portuguese colonists started banana plantations in the Atlantic Islands, Brazil, and western Africa.[55] North Americans began consuming bananas on a small scale at very high prices shortly after the Civil War, though it was only in the 1880s that it became more widespread.[56] As late as the Victorian Era, bananas were not widely known in Europe, although they were available.[55] Jules Verne introduces bananas to his readers with detailed descriptions in Around the World in Eighty Days (1872).

text: The earliest modern plantations originated in Jamaica and the related Western Caribbean Zone, including most of Central America. It involved the combination of modern transportation networks of steamships and railroads with the development of refrigeration that allowed bananas to have more time between harvesting and ripening. North America shippers like Lorenzo Dow Baker and Andrew Preston, the founders of the Boston Fruit Company started this process in the 1870s, but railroad builders like Minor C Keith also participated, eventually culminating in the multi-national giant corporations like today's Chiquita Brands International and Dole.[56] These companies were monopolistic, vertically integrated (meaning they controlled growing, processing, shipping and marketing) and usually used political manipulation to build enclave economies (economies that were internally self-sufficient, virtually tax exempt, and export oriented that contribute very little to the host economy). Their political maneuvers, which gave rise to the term Banana republic for states like Honduras and Guatemala, included working with local elites and their rivalries to influence politics or playing the international interests of the United States, especially during the Cold War, to keep the political climate favorable to their interests.[57]

text: Peasant cultivation for export in the Caribbean

text: The vast majority of the world's bananas today are cultivated for family consumption or for sale on local markets. India is the world leader in this sort of production, but many other Asian and African countries where climate and soil conditions allow cultivation also host large populations of banana growers who sell at least some of their crop.[58]

text: There are peasant sector banana growers who produce for the world market in the Caribbean, however. The Windward Islands are notable for the growing, largely of Cavendish bananas, for an international market, generally in Europe but also in North America. In the Caribbean, and especially in Dominica where this sort of cultivation is widespread, holdings are in the 1–2 acre range. In many cases the farmer earns additional money from other crops, from engaging in labor outside the farm, and from a share of the earnings of relatives living overseas. This style of cultivation often was popular in the islands as bananas required little labor input and brought welcome extra income.[citation needed] Banana crops are vulnerable to destruction by high winds, such as tropical storms or cyclones.[59]

text: After the signing of the NAFTA agreements in the 1990s, however, the tide turned against peasant producers. Their costs of production were relatively high and the ending of favorable tariff and other supports, especially in the European Economic Community, made it difficult for peasant producers to compete with the bananas grown on large plantations by the well capitalized firms like Chiquita and Dole. Not only did the large companies have access to cheap labor in the areas they worked, but they were better able to afford modern agronomic advances such as fertilization. The "dollar banana" produced by these concerns made the profit margins for peasant bananas unsustainable.[citation needed]

text: Caribbean countries have sought to redress this problem by providing government supported agronomic services and helping to organize producers' cooperatives. They have also been supporters of the Fair Trade movement which seeks to balance the inequities in the world trade in commodities.[citation needed]

text: East Africa

text: Most farms supply local consumption. Cooking bananas represent a major food source and a major income source for smallhold farmers. In east Africa, highland bananas are of greatest importance as a staple food crop. In countries such as Uganda, Burundi, and Rwanda per capita consumption has been estimated at 45 kilograms (99 lb) per year, the highest in the world.[citation needed]

text: Modern cultivation

text: All widely cultivated bananas today descend from the two wild bananas Musa acuminata and Musa balbisiana. While the original wild bananas contained large seeds, diploid or polyploid cultivars (some being hybrids) with tiny seeds are preferred for human raw fruit consumption.[60] These are propagated asexually from offshoots. The plant is allowed to produce two shoots at a time; a larger one for immediate fruiting and a smaller "sucker" or "follower" to produce fruit in 6–8 months. The life of a banana plantation is 25 years or longer, during which time the individual stools or planting sites may move slightly from their original positions as lateral rhizome formation dictates.[citation needed]

text: Cultivated bananas are parthenocarpic, i.e. the flesh of the fruit swells and ripens without its seeds being fertilized and developing. Lacking viable seeds, propagation typically involves farmers removing and transplanting part of the underground stem (called a corm). Usually this is done by carefully removing a sucker (a vertical shoot that develops from the base of the banana pseudostem) with some roots intact. However, small sympodial corms, representing not yet elongated suckers, are easier to transplant and can be left out of the ground for up to two weeks; they require minimal care and can be shipped in bulk.[citation needed]

text: It is not necessary to include the corm or root structure to propagate bananas; severed suckers without root material can be propagated in damp sand, although this takes somewhat longer.[citation needed]

text: In some countries, commercial propagation occurs by means of tissue culture. This method is preferred since it ensures disease-free planting material. When using vegetative parts such as suckers for propagation, there is a risk of transmitting diseases (especially the devastating Panama disease).[citation needed]

text: As a non-seasonal crop, bananas are available fresh year-round.[61]

text: Cavendish

text: In global commerce in 2009, by far the most important cultivars belonged to the triploid AAA group of Musa acuminata, commonly referred to as Cavendish group bananas. They accounted for the majority of banana exports,[60] despite only coming into existence in 1836.[62] The cultivars Dwarf Cavendish and Grand Nain (Chiquita Banana) gained popularity in the 1950s after the previous mass-produced cultivar, Gros Michel (also an AAA group cultivar), became commercially unviable due to Panama disease, caused by the fungus Fusarium oxysporum which attacks the roots of the banana plant.[60] Cavendish cultivars are resistant to the Panama Disease but in 2013 there were fears that the Black Sigatoka fungus would in turn make Cavendish bananas unviable.[63]

text: Ease of transport and shelf life rather than superior taste make the Dwarf Cavendish the main export banana.[citation needed]

text: Even though it is no longer viable for large scale cultivation, Gros Michel is not extinct and is still grown in areas where Panama disease is not found.[64] Likewise, Dwarf Cavendish and Grand Nain are in no danger of extinction, but they may leave supermarket shelves if disease makes it impossible to supply the global market. It is unclear if any existing cultivar can replace Cavendish bananas, so various hybridisation and genetic engineering programs are attempting to create a disease-resistant, mass-market banana.[60]

text: Ripening

text: Export bananas are picked green, and ripen in special rooms upon arrival in the destination country. These rooms are air-tight and filled with ethylene gas to induce ripening. The vivid yellow color consumers normally associate with supermarket bananas is, in fact, caused by the artificial ripening process.[65][66] Flavor and texture are also affected by ripening temperature. Bananas are refrigerated to between 13.5 and 15 °C (56.3 and 59.0 °F) during transport. At lower temperatures, ripening permanently stalls, and the bananas turn gray as cell walls break down. The skin of ripe bananas quickly blackens in the 4 °C (39 °F) environment of a domestic refrigerator, although the fruit inside remains unaffected.

text: "Tree-ripened" Cavendish bananas have a greenish-yellow appearance which changes to a brownish-yellow as they ripen further. Although both flavor and texture of tree-ripened bananas is generally regarded as superior to any type of green-picked fruit,[citation needed] this reduces shelf life to only 7–10 days.[citation needed]

text: Bananas can be ordered by the retailer "ungassed" (i.e. not treated with ethylene), and may show up at the supermarket fully green. Guineos verdes (green bananas) that have not been gassed will never fully ripen before becoming rotten. Instead of fresh eating, these bananas can be used for cooking, as seen in Jamaican cuisine.[67]

text: A 2008 study reported that ripe bananas fluoresce when exposed to ultraviolet light. This property is attributed to the degradation of chlorophyll leading to the accumulation of a fluorescent product in the skin of the fruit. The chlorophyll breakdown product is stabilized by a propionate ester group. Banana-plant leaves also fluoresce in the same way. Green bananas do not fluoresce. The study suggested that this allows animals which can see light in the ultraviolet spectrum (tetrachromats and pentachromats) to more easily detect ripened bananas.[68]

text: Storage and transport

text: Bananas must be transported over long distances from the tropics to world markets.[69] To obtain maximum shelf life, harvest comes before the fruit is mature. The fruit requires careful handling, rapid transport to ports, cooling, and refrigerated shipping. The goal is to prevent the bananas from producing their natural ripening agent, ethylene. This technology allows storage and transport for 3–4 weeks at 13 °C (55 °F). On arrival, bananas are held at about 17 °C (63 °F) and treated with a low concentration of ethylene. After a few days, the fruit begins to ripen and is distributed for final sale. Unripe bananas can not be held in home refrigerators because they suffer from the cold.[citation needed] Ripe bananas can be held for a few days at home. If bananas are too green, they can be put in a brown paper bag with an apple or tomato overnight to speed up the ripening process.[70]

text: Carbon dioxide (which bananas produce) and ethylene absorbents extend fruit life even at high temperatures. This effect can be exploited by packing banana in a polyethylene bag and including an ethylene absorbent, e.g., potassium permanganate, on an inert carrier. The bag is then sealed with a band or string. This treatment has been shown to more than double lifespans up to 3–4 weeks without the need for refrigeration.[71][72][73]

text: Production and export

text:
Production and export of bananas and plantains by country[Note 1]

Country
Millions
of tonnes
Percentage
of world
total

Table 1: Production (2012)

 India
24.9
18%

 China
10.6
8%

 Uganda
9.8
7%

 Philippines
9.2
7%

 Ecuador
7.6
5%

 Brazil
6.9
5%

 Indonesia
6.2
4%

 Colombia
5.3
4%

 Cameroon
4.9
3%

 Ghana
3.6
3%

All other countries
50.2
36%

Total world
139.2
100%

Table 2: Exports (2011)

 Ecuador
5.2
29%

 Costa Rica
1.8
10%

 Colombia
1.8
10%

 Philippines
1.6
9%

 Guatemala
1.5
8%

All other countries
6.0
34%

Total world
17.9
100%

tag: table

text: Statistics on the production and export of bananas and plantains are available from the Food and Agriculture Organization. Some countries produce statistics which distinguish between bananas and plantains, but two of the top three producers (India and China) do not, so comparisons can only be made using the total for bananas and plantains combined. The 2012 statistics (see Table 1) show that India led the world in banana production, producing around 18% of the worldwide crop of 139 million metric tonnes. Philippines was the next largest producer with around 7% of the worldwide crop. Its national data does distinguish between bananas and plantains, and shows that the latter made up over 95% of production. Ten countries produced around two thirds of the total world production.[Note 1]

text: The statistics for the export of bananas and plantains show a rather different picture (see Table 2). Total world exports at around 18 million metric tonnes amounted to only 12% of total world production; two thirds of the exports were generated by only five countries. The top three producing countries do not appear in this table, and two countries, Costa Rica and Guatemala, do not appear in the table of top producers. Only the Philippines has a consistent position in both tables. Exports were dominated by Ecuador, with 29% of the world total. Statistics for Ecuador distinguish between bananas and plantains; 93% of its exports were classified as bananas.[Note 1]

text: Bananas and plantains constitute a major staple food crop for millions of people in developing countries.[69] In most tropical countries, green (unripe) bananas used for cooking represent the main cultivars. Bananas are cooked in ways that are similar to potatoes. Both can be fried, boiled, baked, or chipped and have similar taste and texture when served. One banana provides about the same calories as one potato.[citation needed]

text: Most producers are small-scale farmers either for home consumption or local markets. Because bananas and plantains produce fruit year-round, they provide an extremely valuable food source during the hunger season (when the food from one annual/semi-annual harvest has been consumed, and the next is still to come). Bananas and plantains are therefore critical to global food security.

text: Bananas have been an important source of disagreement in the Doha Round of trade talks. A study for ICTSD showed that the new deal on EU banana import tariffs will be a boon to Latin American exporters but would trigger a drop in exports of the fruit from African, Caribbean and Pacific (ACP) countries.[74]

text: Bananas are among the most widely consumed foods in the world. Chiquita, Del Monte, Dole, and Fyffes grow their own bananas in Ecuador, Colombia, Costa Rica, Guatemala, and Honduras. Banana plantations are capital intensive and demand significant expertise. The majority of independent growers are large and wealthy landowners in these countries. Producers have attempted to raise prices via marketing them as "fair trade" or Rainforest Alliance-certified in some countries.[citation needed]

text: The banana has an extensive trade history starting with firms such as the Irish Fyffes and the US United Fruit Company (now Chiquita) at the end of the 19th century. For much of the 20th century, bananas and coffee dominated the export economies of Central America. In the 1930s, bananas and coffee made up as much as 75% of the region's exports. As late as 1960, the two crops accounted for 67% of the exports from the region. Though the two were grown in similar regions, they tended not to be distributed together. The United Fruit Company based its business almost entirely on the banana trade, because the coffee trade proved too difficult to control. The term "banana republic" has been applied to most countries in Central America, but from a strict economic perspective only Costa Rica, Honduras, and Panama had economies dominated by the banana trade.[citation needed]

text: The European Union has traditionally imported many of its bananas from former European Caribbean colonies, paying guaranteed prices above global market rates (see Lomé Convention). These arrangements have now been largely withdrawn under pressure from other major trading powers, principally the United States. The withdrawal of these indirect subsidies to Caribbean producers is expected to favour the more efficient banana producers of Central America, in which American companies have an economic interest. In addition, small-scale Caribbean producers are finding it difficult to comply with increasingly strict certification requirements. Some support is being provided to Caribbean countries under the EU's Banana Accompanying Measures (BAM).[75]

text: The United States produces few bananas. A mere 14,000 tonnes (14,000 long tons; 15,000 short tons) were grown in Hawaii in 2001.[76] Bananas were once grown in Florida[77] and southern California.[78] In 2012, the United States imported 27 percent of all bananas traded internationally, a total of approximately 4,350,000 tonnes (4,280,000 long tons; 4,800,000 short tons) of bananas with an import cost of almost $4.3 billion (equivalent to $4.5 billion in 2016).[79]

text: In March 2014 it was announced that Fyffes and Chiquita would merge to create the world's largest banana company, worth about $1bn (£597m). The new firm, named ChiquitaFyffes, is expected to sell about 160 million boxes of bananas annually.[80]

text: Pests, diseases, and natural disasters

text: While in no danger of outright extinction, the most common edible banana cultivar Cavendish (extremely popular in Europe and the Americas) could become unviable for large-scale cultivation in the next 10–20 years. Its predecessor 'Gros Michel', discovered in the 1820s, suffered this fate. Like almost all bananas, Cavendish lacks genetic diversity, which makes it vulnerable to diseases, threatening both commercial cultivation and small-scale subsistence farming.[81][82] Some commentators remarked that those variants which could replace what much of the world considers a "typical banana" are so different that most people would not consider them the same fruit, and blame the decline of the banana on monogenetic cultivation driven by short-term commercial motives.[57]

text: Panama disease

text: Panama disease is caused by a fusarium soil fungus (Race 1), which enters the plants through the roots and travels with water into the trunk and leaves, producing gels and gums that cut off the flow of water and nutrients, causing the plant to wilt, and exposing the rest of the plant to lethal amounts of sunlight. Prior to 1960, almost all commercial banana production centered on "Gros Michel", which was highly susceptible.[83] Cavendish was chosen as the replacement for Gros Michel because, among resistant cultivars, it produces the highest quality fruit. However, more care is required for shipping the Cavendish, and its quality compared to Gros Michel is debated.[by whom?][citation needed]

text: According to current sources, a deadly form of Panama disease is infecting Cavendish. All plants are genetically identical, which prevents evolution of disease resistance. Researchers are examining hundreds of wild varieties for resistance.[83]

text: Tropical race 4

text: Tropical race 4 (TR4) is a reinvigorated strain of Panama disease first discovered in 1993. This virulent form of fusarium wilt has wiped out Cavendish in several southeast Asian countries. It has yet to reach the Americas; however, soil fungi can easily be carried on boots, clothing, or tools. This is how TR4 travels and is its most likely route into Latin America. Cavendish is highly susceptible to TR4, and over time, Cavendish is almost certain to be eliminated from commercial production by this disease. The only known defense to TR4 is genetic resistance.[84]

text: Black sigatoka

text: Black sigatoka is a fungal leaf spot disease first observed in Fiji in 1963 or 1964. Black Sigatoka (also known as black leaf streak) has spread to banana plantations throughout the tropics from infected banana leaves that were used as packing material. It affects all main cultivars of bananas and plantains (including the Cavendish cultivars[63]), impeding photosynthesis by blackening parts of the leaves, eventually killing the entire leaf. Starved for energy, fruit production falls by 50% or more, and the bananas that do grow ripen prematurely, making them unsuitable for export. The fungus has shown ever-increasing resistance to treatment, with the current expense for treating 1 hectare (2.5 acres) exceeding $1,000 per year. In addition to the expense, there is the question of how long intensive spraying can be environmentally justified. Several resistant cultivars of banana have been developed, but none has yet received commercial acceptance due to taste and texture issues.[citation needed]

text: In East Africa

text: With the arrival of black sigatoka, banana production in eastern Africa fell by over 40%. For example, during the 1970s, Uganda produced 15 to 20 tonnes (15 to 20 long tons; 17 to 22 short tons) of bananas per hectare. Today, production has fallen to only 6 tonnes (5.9 long tons; 6.6 short tons) per hectare.[citation needed]

text: The situation has started to improve as new disease-resistant cultivars have been developed by the International Institute of Tropical Agriculture and the National Agricultural Research Organisation of Uganda (NARO), such as FHIA-17 (known in Uganda as the Kabana 3). These new cultivars taste different from the Cabana banana, which has slowed their acceptance by local farmers. However, by adding mulch and manure to the soil around the base of the plant, these new cultivars have substantially increased yields in the areas where they have been tried.[citation needed]

text: The International Institute of Tropical Agriculture and NARO, funded by the Rockefeller Foundation and CGIAR have started trials for genetically modified bananas that are resistant to both Black sigatoka and banana weevils. It is developing cultivars specifically for smallholder and subsistence farmers.[citation needed]

text: Banana bunchy top virus

text: Banana bunchy top virus (BBTV) jumps from plant to plant using aphids. It stunts leaves, resulting in a "bunched" appearance. Generally, an infected plant does not produce fruit, although mild strains exist which allow some production. These mild strains are often mistaken for malnourishment, or a disease other than BBTV. There is no cure; however, its effect can be minimized by planting only tissue-cultured plants (in vitro propagation), controlling aphids, and immediately removing and destroying infected plants.[citation needed]

text: Banana bacterial wilt

text: Banana bacterial wilt (BBW) is a bacterial disease caused by Xanthomonas campestris pv. musacearum.[85] After being originally identified on a close relative of bananas, Ensete ventricosum, in Ethiopia in the 1960s,[86] BBW occurred in Uganda in 2001 affecting all banana cultivars. Since then BBW has been diagnosed in Central and East Africa including the banana growing regions of Rwanda, the Democratic Republic of the Congo, Tanzania, Kenya, Burundi, and Uganda.[87]

text: Nutrition

text:
Bananas, raw (Daily Value)

Nutritional value per 100 g (3.5 oz)

Energy
371 kJ (89 kcal)

Carbohydrates

22.84 g

Sugars
12.23 g

Dietary fiber
2.6 g

Fat

0.33 g

Protein

1.09 g

Vitamins

Thiamine (B1)

(3%)
0.031 mg

Riboflavin (B2)

(6%)
0.073 mg

Niacin (B3)

(4%)
0.665 mg

Pantothenic acid (B5)

(7%)
0.334 mg

Vitamin B6

(31%)
0.4 mg

Folate (B9)

(5%)
20 μg

Choline

(2%)
9.8 mg

Vitamin C

(10%)
8.7 mg

Minerals

Iron

(2%)
0.26 mg

Magnesium

(8%)
27 mg

Manganese

(13%)
0.27 mg

Phosphorus

(3%)
22 mg

Potassium

(8%)
358 mg

Sodium

(0%)
1 mg

Zinc

(2%)
0.15 mg

Other constituents

Water
74.91 g

Link to USDA Database entry values are for edible portion

Units
μg = micrograms • mg = milligrams
IU = International units

Percentages are roughly approximated using US recommendations for adults.
Source: USDA Nutrient Database

text: Raw bananas (not including the peel) are 75% water, 23% carbohydrates, 1% protein, and contain negligible fat (table). In a 100 gram amount, bananas supply 89 Calories and are a rich source of vitamin B6, providing 31% of the US recommended Daily Value, and contain moderate amounts of vitamin C, manganese and dietary fiber (table).

text: Although bananas are commonly thought to supply exceptional potassium content,[88] their actual potassium content is relatively low per typical food serving at only 8% of the US recommended Daily Value (table). Vegetables with higher potassium content than raw dessert bananas (358 mg per 100 grams) include raw spinach (558 mg per 100 grams), baked potatoes without skin (391 mg per 100 grams), cooked soybeans (539 mg per 100 grams), grilled portabella mushrooms (437 mg per 100 grams) and processed tomato sauces (413–439 mg per 100 grams). Raw plantains contain 499 mg potassium per 100 grams. Dehydrated dessert bananas or banana powder contain 1491 mg potassium per 100 grams.[89]

text: Individuals with a latex allergy may experience a reaction to bananas.[90]

text: Culture

text: Food and cooking

text: Fruit

text: Bananas are a staple starch for many tropical populations. Depending upon cultivar and ripeness, the flesh can vary in taste from starchy to sweet, and texture from firm to mushy. Both the skin and inner part can be eaten raw or cooked. The primary component of the aroma of fresh bananas is isoamyl acetate (also known as banana oil), which, along with several other compounds such as butyl acetate and isobutyl acetate, is a significant contributor to banana flavor.[91][92][93]

text: During the ripening process, bananas produce the gas ethylene, which acts as a plant hormone and indirectly affects the flavor. Among other things, ethylene stimulates the formation of amylase, an enzyme that breaks down starch into sugar, influencing the taste of bananas. The greener, less ripe bananas contain higher levels of starch and, consequently, have a "starchier" taste. On the other hand, yellow bananas taste sweeter due to higher sugar concentrations. Furthermore, ethylene signals the production of pectinase, an enzyme which breaks down the pectin between the cells of the banana, causing the banana to soften as it ripens.[94][95]

text: Bananas are eaten deep fried, baked in their skin in a split bamboo, or steamed in glutinous rice wrapped in a banana leaf. Bananas can be made into jam. Banana pancakes are popular amongst backpackers and other travelers in South Asia and Southeast Asia. This has elicited the expression Banana Pancake Trail for those places in Asia that cater to this group of travelers. Banana chips are a snack produced from sliced dehydrated or fried banana or plantain, which have a dark brown color and an intense banana taste. Dried bananas are also ground to make banana flour. Extracting juice is difficult, because when a banana is compressed, it simply turns to pulp. Bananas feature prominently in Philippine cuisine, being part of traditional dishes and desserts like maruya, turón, and halo-halo or saba con yelo. Most of these dishes use the Saba or Cardaba banana cultivar. Bananas are also commonly used in cuisine in the South-Indian state of Kerala, where they are steamed (puzhungiyathu), made into curries,[96] fried into chips (upperi)[97] or fried in batter (pazhampori).[98] Pisang goreng, bananas fried with batter similar to the Filipino maruya or Kerala pazhampori, is a popular dessert in Malaysia, Singapore, and Indonesia. A similar dish is known in the United Kingdom and United States as banana fritters.

text: Plantains are used in various stews and curries or cooked, baked or mashed in much the same way as potatoes, such as the Pazham Pachadi prepared in Kerala.[96]

text: Seeded bananas (Musa balbisiana), one of the forerunners of the common domesticated banana,[99] are sold in markets in Indonesia.[citation needed]

text: Flower

text: Banana hearts are used as a vegetable[100] in South Asian and Southeast Asian cuisine, either raw or steamed with dips or cooked in soups, curries and fried foods.[101] The flavor resembles that of artichoke. As with artichokes, both the fleshy part of the bracts and the heart are edible.[102]

text: Leaves

text: Banana leaves are large, flexible, and waterproof. They are often used as ecologically friendly disposable food containers or as "plates" in South Asia and several Southeast Asian countries. In Indonesian cuisine, banana leaf is employed in cooking method called pepes and botok; the banana leaf packages containing food ingredients and spices are cooked on steam, in boiled water or grilled on charcoal. In the South Indian states of Tamil Nadu, Karnataka, Andhra Pradesh and Kerala in every occasion the food must be served in a banana leaf and as a part of the food a banana is served. Steamed with dishes they impart a subtle sweet flavor. They often serve as a wrapping for grilling food. The leaves contain the juices, protect food from burning and add a subtle flavor.[103] In Tamil Nadu (India) leaves are fully dried and used as packing material for food stuffs and also making cups to hold liquid foods. In Central American countries, banana leaves are often used as wrappers for tamales.[citation needed]

text: Trunk

text: The tender core of the banana plant's trunk is also used in South Asian and Southeast Asian cuisine, and notably in the Burmese dish mohinga.

text: Fiber

text: Textiles

text: Banana fiber harvested from the pseudostems and leaves of the plant has been used for textiles in Asia since at least the 13th century. Both fruit-bearing and fibrous varieties of the banana plant have been used.[104] In the Japanese system Kijōka-bashōfu, leaves and shoots are cut from the plant periodically to ensure softness. Harvested shoots are first boiled in lye to prepare fibers for yarn-making. These banana shoots produce fibers of varying degrees of softness, yielding yarns and textiles with differing qualities for specific uses. For example, the outermost fibers of the shoots are the coarsest, and are suitable for tablecloths, while the softest innermost fibers are desirable for kimono and kamishimo. This traditional Japanese cloth-making process requires many steps, all performed by hand.[105]

text: In a Nepalese system the trunk is harvested instead, and small pieces are subjected to a softening process, mechanical fiber extraction, bleaching and drying. After that, the fibers are sent to the Kathmandu Valley for use in rugs with a silk-like texture. These banana fiber rugs are woven by traditional Nepalese hand-knotting methods, and are sold RugMark certified.[citation needed]

text: In South Indian state of Tamil Nadu after harvesting for fruit the trunk (outer layer of the shoot) is made into fine thread used in making of flower garlands instead of thread.[citation needed]

text: In India, a banana fiber separator machine has been developed, which takes the agricultural waste of local banana harvests and extracts strands of the fiber.[106]

text: Paper

text: Banana fiber is used in the production of banana paper. Banana paper is made from two different parts: the bark of the banana plant, mainly used for artistic purposes, or from the fibers of the stem and non-usable fruits. The paper is either hand-made or by industrial process.[107]

text: Cultural roles

text: Arts

text:
The song "Yes! We Have No Bananas" was written by Frank Silver and Irving Cohn and originally released in 1923; for many decades, it was the best-selling sheet music in history. Since then the song has been rerecorded several times and has been particularly popular during banana shortages.[108][109]
A person slipping on a banana peel has been a staple of physical comedy for generations. An American comedy recording from 1910 features a popular character of the time, "Uncle Josh", claiming to describe his own such incident:[110]

text: Now I don't think much of the man that throws a banana peelin' on the sidewalk, and I don't think much of the banana peel that throws a man on the sidewalk neither ... my foot hit the bananer peelin' and I went up in the air, and I come down ker-plunk, jist as I was pickin' myself up a little boy come runnin' across the street ... he says, "Oh mister, won't you please do that agin? My little brother didn't see you do it."

text:
The poet Bashō is named after the Japanese word for a banana plant. The "bashō" planted in his garden by a grateful student became a source of inspiration to his poetry, as well as a symbol of his life and home.[111]
The cover artwork for the debut album of The Velvet Underground features a banana made by Andy Warhol. On the original vinyl LP version, the design allowed the listener to "peel" this banana to find a pink, peeled phallic banana on the inside.[112]

text: Religion and popular beliefs

text: In Burma, bunches of green bananas surrounding a green coconut in a tray form an important part of traditional offerings to the Buddha and the Nats.[citation needed]

text: In all the important festivals and occasions of Hindus, the serving of bananas plays a prominent part. Traditionally in Tamil marriages, banana plants are tied on both sides of the entrance of houses to bless the newlyweds to be useful to each other.[citation needed] The banana is one of three fruits with this significance, the others being mango and jack fruit.[citation needed]

text: In Thailand, it is believed that a certain type of banana plants may be inhabited by a spirit, Nang Tani, a type of ghost related to trees and similar plants that manifests itself as a young woman.[113] Often people tie a length of colored satin cloth around the pseudostem of the banana plants.[114]

text: In Malay folklore, the ghost known as Pontianak is associated with banana plants (pokok pisang), and its spirit is said to reside in them during the day.[115]

text: Racist symbol

text: There is a long racist history of describing people of African descent as being more like monkeys than humans, and due to the assumption in popular culture that monkeys like bananas, bananas have been used in symbolic acts of hate speech.[116][117] In April 2014, during a match at Villarreal's stadium, El Madrigal, Dani Alves was targeted by Villareal supporter David Campaya Lleo, who threw a banana at him.[118] Alves picked up the banana, peeled it and took a bite, and the meme went viral on social media in support of him.[119] Racist taunts are an ongoing problem in football.[120][121] Bananas were hung from nooses around the campus of American University in May 2017 after the student body elected its first black woman student government president.[122]

text: Unicode

text: The Unicode standard includes the emoji character U+1F34C 🍌 BANANA (HTML 🍌).[123]

text: Other uses

text:
The large leaves may be used as umbrellas.[103]
Banana peel may have capability to extract heavy metal contamination from river water, similar to other purification materials.[124][125] In 2007, banana peel powder was tested as a means of filtration for heavy metals and radionuclides occurring in water produced by the nuclear and fertilizer industries (cadmium contaminant is present in phosphates). When added and thoroughly mixed for 40 minutes, the powder can remove roughly 65% of heavy metals, and this can be repeated.

text: Gallery

text:
Peeled, whole, and longitudinal section

A bunch of Cavendish bananas

Kilawin na pusô ng saging, a Filipino dish using banana flowers

Nicaraguan Nacatamales, in banana leaves, ready to be steamed

Kaeng yuak is a northern Thai curry made with the core of the banana plant

Pisang goreng fried banana coated in batter, popular snack in Indonesia

Banana in sweet gravy, known as pengat pisang in Malaysia.

Banana 'tree' showing fruit and inflorescence.

Banana inflorescence, partially opened

Female flowers have petals and other flower parts at the tip of the ovary

Wild banana with flowers and stem growing in reverse direction seen in Kodagu, India

text: Notes

text: ^ Jump up to: a b c The figures in the tables were derived from: "FAOSTAT". Food and Agriculture Organization of the United Nations.  The datasets for bananas and plantains for 2012 (export dataset 2011) were downloaded and combined (the two are not distinguished in many cases). Totals and percentages were then calculated. The number of countries shown was chosen to account for a minimum of 66% of the world total.

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