131 Sentences With "hypocenter" | Random Sentence Generator

Now, where the shaking actually happens, that's called the hypocenter.

Hiroshima city and bay area with location of the A-bomb hypocenter.

While previous models have suggested three locations for a hypocenter, this result reveals that only a hypocenter to the south of Point Reyes, California, would recreate the eastward, then westward tipping of the train, according to the paper published in Seismological Research Letters.

This man was exposed within 1 kilometer of the hypocenter of the atom bomb dropped on Aug.

This leaves a hypocenter offshore from San Francisco or near the California city of San Juan Bautista, confirming previous estimates.

Six-year-old Sachiko was playing outside with friends half a mile from the hypocenter when the bomb fell on Nagasaki on Aug.

The ruin, which is the only structure left standing near the bomb's hypocenter, serves as a memorial to the people killed in the bombing.

The memorial at Hiroshima makes a statement about death and hope by preserving the ruins of a domed hall that stood at the atomic bomb's hypocenter.

Age: 75 | Location: Nagasaki | Distance from hypocenter: 1.2 kilometers You are only givenOne lifeSo cherish this momentCherish this dayBe kind to othersBe kind to yourself 19513 | Nagasaki | 800 meters I pray that every human being finds peace.

At Kerry's suggestion, the ministers also made an impromptu visit to the Atomic Bomb Dome, the remains of the only structure left standing near the hypocenter of the bomb explosion and now a UNESCO World Heritage site.

"The possession of nuclear and other weapons of mass destruction is not the answer (to longings for peace)," Francis said in a message delivered at Nagasaki's Atomic Bomb Hypocenter Park, ground zero of the bomb the United States dropped on Aug.

On top of their analysis of the train tipping, the researchers were able to estimate the location of the earthquake's hypocenter—the area where it actually occurred in the Earth below the epicenter on the surface—based on the train's location and behavior.

On Sunday, Francis will travel to Nagasaki and Hiroshima, where the United States dropped atomic bombs to end World War II. He will deliver a remarks on nuclear weapons in the Nagasaki Atomic Bomb Hypocenter Park and celebrate a mass in the city's baseball stadium.

Hypocenter (Focus) and epicenter of an earthquake A hypocenter (or hypocentre) (from [hypόkentron] for 'below the center') is the point of origin of an earthquake or a subsurface nuclear explosion. In seismology, it is a synonym of the focus. The term hypocenter is also used as a synonym for ground zero, the surface point directly beneath a nuclear airburst.

The rupture propagated unilaterally from the hypocenter towards the southeast.

With adjustments for velocity changes, the initial estimate of the hypocenter is made, then a series of linear equations is set up, one for each station. The equations express the difference between the observed arrival times and those calculated from the initial estimated hypocenter. These equations are solved by the method of least squares which minimizes the sum of the squares of the differences between the observed and calculated arrival times, and a new estimated hypocenter is computed. The system iterates until the location is pinpointed within the margin of error for the velocity computations.

An earthquake's hypocenter is the position where the strain energy stored in the rock is first released, marking the point where the fault begins to rupture.The hypocenter is the point within the earth where an earthquake rupture starts. The epicenter is the point directly above it at the surface of the Earth. Also commonly termed the focus.

Within the castle walls, three trees survived the atomic bombing: a eucalyptus and a willow at approximately 740 m from the hypocenter, and a holly approximately 935 m from the hypocenter. Both specimens are preserved just beyond the Honmaru. Also located inside the Honmaru is the concrete bunker from which the first radio broadcast out of Hiroshima following the atomic bombing was made.

Miyake cites his first encounter with design as two bridges his home-town, Hiroshima at the hypocenter of the atomic bombing of the city in WWII.

It was empty and quiet around, only the radiometers were clicking, noting us of the increased level of radiation. The troops proceeded past the hypocenter, outside of the area of severe radioactive contamination. Directly in the zone adjacent to the hypocenter of the explosion, the ground was covered with a thin glassy crust of melted sand, crunchy and breaking underfoot, like a thin ice on spring puddles after a night frost.

When the bomb was dropped at 11:02 A.M. on August 9, 1945, the 20 neighborhoods within a one-kilometer radius of the hypocenter were completely destroyed by the heat flash and blast winds generated by the explosion. They were then reduced to ashes by the fires which followed. Within 2 km of the hypocenter, roughly 80% of the houses collapsed and burned. When the smoke cleared, the area was strewn with corpses.

The most destructive earthquake in recent Guatemalan history was the 1976 quake with a magnitude of 7.5 Mw and a hypocenter depth of just 5 km. This shallow-focus earthquake, originating from the Motagua Fault, caused 23,000 fatalities, leaving 76,000 injured and causing widespread material damage. Surprisingly, the 7.9 Mw earthquake of 1942, though higher in magnitude, was much less destructive, in part because of its substantially deeper hypocenter depth of 60 km.

In its most general sense, the word earthquake is used to describe any seismic event—whether natural or caused by humans—that generates seismic waves. Earthquakes are caused mostly by rupture of geological faults but also by other events such as volcanic activity, landslides, mine blasts, and nuclear tests. An earthquake's point of initial rupture is called its hypocenter or focus. The epicenter is the point at ground level directly above the hypocenter.

The fault plane was 90 km long and 45 km wide. The maximum slip was about 2.5 m, which was located about 20 and 40 km WNW of the hypocenter.

Technical improvements are being made to increase the hit rate, including the Integrated Particle Filter (IPF) and Propagation of Local Undamped Motion (PLUM) methods. The IPF method, introduced on 14 December 2016, obtains seismic source elements with a particle filter. The PLUM method, introduced on 22 March 2018, predicts the seismic intensity directly from observed intensity without estimating the hypocenter and scale. Accurate seismic-intensity forecasts can be made for large earthquakes or those whose hypocenter is unknown.

The depth to the hypocenter can be estimated by comparing the sizes of different isoseismal areas. In shallow earthquakes, the lines are close together, while in deep events the lines are spread further apart.

It was founded in 1948. Town status was granted to it on February 1, 1963.. It was one of the towns closest to the hypocenter of the blast from the 2013 Russian meteor event.

Essentials of Ultrasound Physics, James A. Zagzebski, Mosby Inc., 1996. Attenuation also occurs in earthquakes; when the seismic waves move farther away from the hypocenter, they grow smaller as they are attenuated by the ground.

On 28 December 1943, earthquakes starting to occur frequently around Mount Usu, with occurrences of more than 200 times per day on some days. The hypocenter in the early days was located in the vicinity of Lake Tōya. As the year entered 1944, the hypocenter started to move toward the eastern part of the base of Mount Usu and this resulted in the protuberance of the overlying ground. Eventually the protuberance started to spread to the north, reaching up to heights of 50 meters in some areas.

This can prevent the loss of life as well as inventory. Businesses that did not sustain very much damage also gained a sense of security that may be unreliable as the moment magnitude was high but the hypocenter was deep under the earth. This earthquake was a 6.8 moment magnitude that caused $2 billion damage while the Northridge earthquake was a 6.7 moment magnitude, but caused more than $20 billion worth of damage as the hypocenter of the Northridge earthquake was much shallower and closer to the surface of the earth.

Investigations using Interferometric synthetic aperture radar (InSAR), combined with field and seismological observations, have identified two fault segments with slightly differing strikes, with the hypocenter and most of the displacement being on the more southerly of the segments.

One of the few trees to survive the blast from the 6 August 1945 atomic bombing of Hiroshima Japan, was an E. melliodora. The tree was located from the hypocenter, and as of April 2019 was still standing.

The hypocenter/epicenter of an earthquake is calculated by using the seismic data of that earthquake from at least three different locations. The hypocenter/epicenter is found at the intersection of three circles centered on three observation stations, here shown in Japan, Australia and the United States. The radius of each circle is calculated from the difference in the arrival times of P- and S-waves at the corresponding station. In the case of local or nearby earthquakes, the difference in the arrival times of the P and S waves can be used to determine the distance to the event.

In the case of earthquakes that have occurred at global distances, three or more geographically diverse observing stations (using a common clock) recording P-wave arrivals permits the computation of a unique time and location on the planet for the event. Typically, dozens or even hundreds of P-wave arrivals are used to calculate hypocenters. The misfit generated by a hypocenter calculation is known as "the residual". Residuals of 0.5 second or less are typical for distant events, residuals of 0.1–0.2 s typical for local events, meaning most reported P arrivals fit the computed hypocenter that well.

As its hypocenter was over deep, the shock was felt across the whole of northern Italy, but caused little damage. Between 1740 and 2000, the Garfagnana region experienced 16 earthquakes rated as "strong" or above (VI or greater on the Mercalli scale).

A tsunami warning was issued, but was soon downgraded to a tsunami advisory for much of the Aleutian Islands; however, the hypocenter was too deep to generate a tsunami that would affect the Pacific basin. A small non-destructive tsunami was generated.

The surface of the Earth acts like a mirror. A wave that runs up against it cannot travel into the air, so it is reflected back down into the Earth, traveling to the same seismograph that recorded the direct wave a little bit earlier. The time delay of the reflected wave depends of course directly on the extra distance it has traveled: from the hypocenter up to the surface and back down to the depth of the hypocenter. This method works fine, if the hypocentral depth Z>50 km because, in that case, the direct and reflected phases (waves) are clearly separated on the record.

Computing the hypocenters of foreshocks, main shock, and aftershocks of earthquakes allows the three-dimensional plotting of the fault along which movement is occurring. The expanding wavefront from the earthquake's rupture propagates at a speed of several kilometers per second, this seismic wave is what is measured at various surface points in order to geometrically determine an initial guess as to the hypocenter. The wave reaches each station based upon how far away it was from the hypocenter. A number of things need to be taken into account, most importantly variations in the waves speed based upon the materials that it is passing through.

The epicenter, epicentre () or epicentrumOxford English Dictionary: "The point over the centre: applied in Seismol. to the outbreaking point of earthquake shocks." in seismology is the point on the Earth's surface directly above a hypocenter or focus, the point where an earthquake or an underground explosion originates.

Seventy-five percent of Earth's crust is unobservable using solely electromagnetic energy-based geodetic techniques. Seafloor geodesy can now expand geodetic positioning to off-shore environments.Sato, Mariko; Ishikawa, Tadashi; Ujihara, Naoto; Yoshida, Shigeru; Fujita, Masayuki; Mochizuki, Masashi; Asada, Akira. Displacement Above the Hypocenter of the 2011 Tohoku-Oki Earthquake.

It studied the effect of the nuclear blast on two wooden frame houses, fifty automobiles and eight bomb shelters designed for residential use. The administration concluded that if windows were left open to prevent the car collapsing on its occupants a car would be "relatively safe" from a small nuclear bomb if at least ten blocks away from the hypocenter. The homes in the study were constructed in such a way as to minimize the thermal effects of Annie, with an eye towards determining if, in the absence of fire, the basement of the closer home — from the hypocenter — might shelter its occupants, while the second — at — could remain standing.Eden (2004), pp. 166-167.

A deep-focus earthquake in seismology (also called a plutonic earthquake) is an earthquake with a hypocenter depth exceeding 300 km. They occur almost exclusively at convergent boundaries in association with subducted oceanic lithosphere. They occur along a dipping tabular zone beneath the subduction zone known as the Wadati–Benioff zone.

The hypocenter of the explosion was the Urakami district, which was a traditionally rustic and isolated suburb. However, the population soared after the 1920s when the district was chosen as the site for munitions factories. An industrial zone was quickly created. Additionally, the Urakami district was home to the Nagasaki Medical College.

The extremely destructive quake killed about 26,200, injured thousands and left more than 75,000 homeless. Approximately 70% of the buildings were destroyed. The earthquake was wrenching because its hypocenter was located just below the city of Bam, around 7 km deep. The Bam area has an underground made of a series of faults.

Surface ruptures commonly occur on pre-existing faults. Only rarely are earthquakes (and surface ruptures) associated with faulting on entirely new fault structures. There is shallow hypocenter, and large fracture energy on the asperities, the asperity shallower than . Examples of such earthquakes are San Fernando earthquake, Tabas earthquake, and Chi-Chi earthquake.

Totskyoe exercise. Measures of safety (Russian) by Sergei Markov An army of 45,000 soldiers marched through the area around the hypocenter soon after the nuclear blast. The exercise was conducted on September 14, 1954, at 9.33 a.m.,Memoirs of Lieutenant-Colonel N. V. Danilenko published in Nuclear Exercises, V. II, 2006, p.

P. 41-600 metres from the hypocenter and avoiding the most dangerous areas of the explosion site. They moved 400–500 metres from the hypocenter, whereas tanks and armoured personnel carriers came even closer. According to the data of remote control and measuring equipment installed at 730 meters from the hypocenter, the level of radiation reached 65 roentgens per hour two minutes after the blast, dropped to 10 R/h after 10 minutes, 2.4 R/h after 25 minutes, and 1.5 R/h after 47 minutes.''Nuclear Exercises'', V. II. 2006. pp. 68-69''Nuclear Exercises'', V. II. 2006. p. 38 In comparison with the rest of the army, the number of troops crossing the blast site was tiny and consisted of only 3,000 soldiers and officers, amounting to only 5-7 percent of the overall number of military forces involved in the exercise.Nuclear Exercises, V. II. 2006. p. 68 Not all of the damage at Totskoye was caused by the nuclear explosion, as two additional non-nuclear bombs were exploded shortly after the main blast in order to imitate a second- wave nuclear strike.

Founded in 1770 as a Cossack village, it has been known as the stanitsa of Yemanzhelinskaya () since 1866. It became a coal mining settlement in 1930–1931, which was granted town status on September 25, 1951.. It was one of the places closest to the hypocenter of the blast from the 2013 Russian meteor event.

Earthquakes create distinct types of waves with different velocities; when reaching seismic observatories, their different travel times help scientists to locate the source of the hypocenter. In geophysics the refraction or reflection of seismic waves is used for research into the structure of the Earth's interior, and man-made vibrations are often generated to investigate shallow, subsurface structures.

Moderate damage was seen in people living in a 1–2 km. radius from the hypocenter, and those people would live for 2–6 weeks. Those people living within a 2–4 km. radius had slight damage, and which would not cause death, but would cause some health problems during the several months after the exposure.

Most recently, in 2012 the Philippine Trench experienced an earthquake of Mw 7.6 (the 2012 Samar earthquake). It hit the trench with a hypocenter depth of 34.9 km. Areas adjacent to the subduction zones have experienced large seismic activity. In 1897, northern Samar experienced a Ms 7.3 earthquake while in 1924 southern Mindanao experienced one with a Ms 8.2.

Several fumaroles reportedly formed in the Yeh Kuning sub-district of Jembrana and released sulfurous fumes. The Jakarta Geophysical Service initially believed the epicenter to be in the Bali Strait, some west of the location observed by the USGS. A subsequent shock of 5.9 occurred at a short distance north, although the hypocenter was at a more shallow .

The first effect of the explosion was blinding light, accompanied by radiant heat from the fireball. The Hiroshima fireball was in diameter, with a surface temperature of . Near ground zero, everything flammable burst into flame. One famous, anonymous Hiroshima victim, sitting on stone steps from the hypocenter, left only a shadow, having absorbed the fireball heat that permanently bleached the surrounding stone.

His scientific interests included seismology, meteorology, astrophysics and theoretical physics. He began his career in seismology with his father. In 1913 he developed a new method for locating the hypocenter of an earthquake and gave an independent verification of discontinuity theory put forward by his father. In 1916 he published an idea of the existence of smaller discontinuities in Earth's crust and mantle.

Hindu temple in Buleleng before 1930. The Braham Arama Vihara Buddhist monastery was heavily damaged and later repaired. According to the United States Geological Survey (USGS), the 14 July shock occurred east-southeast of Jakarta at a depth of although the hypocenter may actually have been as deep as . The main shock lasted for a duration of nearly a minute.

IISEE website Aftershocks came frequently for a few days, and lasted until March 1937. The hypocenter was estimated as 15–18 km, much shallower than the 37–51 km range for other earthquakes in the area. The estimate is disputed, and a revised estimate of 43 km was calculated in 1946 using a macroseismic approach. Later studies have generally supported the initial depth estimate.

Tanaka was 13 years old when Nagasaki was bombed, and his home was around 3.2 kilometres from the hypocenter. He was blown through several panes of glass but did not suffer major injuries. He lost his grandfather, two uncles, an aunt, and a cousin in the bombing. He personally cremated his aunt in a nearby field after she died several days after the bombing.

In the Middle Ages Lorca was the frontier town between Christian and Muslim Spain. Even earlier to that during the Roman period it was ancient Ilura or Heliocroca of the Romans. The city was seriously damaged by a magnitude 5.1 earthquake on 11 May 2011, killing at least nine people. Due to a shallow hypocenter, the earthquake was much more destructive than usual for earthquakes with similar magnitude.

It measured 6.2 on the moment magnitude scale, and approximately 10,000 people died, whilst another 30,000 were injured. The earthquake's hypocenter was around 10 km deep – relatively shallow – allowing shock waves to cause more damage. Because the location does not lie on a plate boundary, there was some debate as to what caused the earthquake. The Indian sub-continent crumples as it pushes against Asia and pressure is released.

Based on observations of ground rupture from SAR interferometry, the earthquake ruptured a 79 km section of the Sarez–Karakul fault zone. This is consistent with the observed distribution of aftershocks and the focal mechanism. Three separate segments were involved, consisting of two longer SW–NE trending segments linked by a shorter more WSW–ENE trending patch forming a restraining bend. The hypocenter is located within the southwesternmost segment.

The 1949 Ambato earthquake was the largest earthquake in the Western Hemisphere in more than five years. On August 5, 1949, it struck Ecuador's Tungurahua Province southeast of its capital Ambato and killed 5,050 people. Measuring 6.4 on the scale, it originated from a hypocenter 15 km beneath the surface. The nearby villages of Guano, Patate, Pelileo, and Pillaro were destroyed, and the city of Ambato suffered heavy damage.

The April 2015 Nepal earthquake (or the Himalayan earthquake) occurred at on 25 April with a moment magnitude (Mw) of 7.8 and a maximum Mercalli Intensity of IX (Violent). Its epicenter was approximately east-southeast of Lamjung, Nepal, and its hypocenter was at a depth of approximately . It is the most powerful disaster to strike Nepal since the 1934 Nepal–Bihar earthquake. The quake killed nearly 8,900 people in Nepal.

Some scientists have speculated that Lake Cheko was created during the Tunguska event of 1908, an explosion that destroyed more than of Siberian taiga. It is suggested that the lake, which lies approximately 8 kilometres north-north-west of the event hypocenter, was formed by a fragment which struck the ground. More recent evidence suggests at least a portion of the lake is over twice as old as the date of the meteorite.

The 2006 Kamchatka earthquakes began on with the occurrence of a very large reverse fault event. This shock had a moment magnitude of 7.6 and a maximum Mercalli intensity of X (Extreme). The hypocenter was located near the coast of Koryak Autonomous Okrug at an estimated depth of 22 km, as reported by the International Seismological Centre. This event caused damage in three villages and was followed by a number of large aftershocks.

The Trinity monument, a rough-sided, lava-rock obelisk about high, marks the explosion's hypocenter. It was erected in 1965 by Army personnel from the White Sands Missile Range using local rocks taken from the western boundary of the range. A simple metal plaque reads: A second memorial plaque on the obelisk was prepared by the Army and the National Park Service, and was unveiled on the 30th anniversary of the test in 1975.

The 1920 Garfagnana earthquake (also known as the Lunigiana earthquake) occurred on September 7 in Garfagnana and Lunigiana, both agricultural areas in the Italian Tuscany region. The quake hypocenter was located beneath Villa Collemandina. The maximum felt intensity was rated as X (Extreme) on the Mercalli intensity scale, and 6.6 on the Richter magnitude scale. It was one of the most destructive seismic events recorded in the Apenninic region in the twentieth century.

Uncertainties in real-time estimates of human losses are a factor of two, at best. One may group the seriousness for introducing errors in the loss estimates due to uncertain input, into three classes: serious, moderate, and negligible. The size of the most serious errors is an order of magnitude (meaning a factor of 10). They can be generated by hypocenter errors, incorrect data on building stock, and magnitude errors for M>8 earthquakes.

The 2011 Burma earthquake () occurred with a magnitude 6.9 on 24 March. It had an epicenter in the eastern part of Shan State in Burma (Myanmar) with a hypocenter 10 km deep.Magnitude 6.8 – MYANMAR It had two aftershocks, one of magnitude 4.8, another at magnitude 5.4, and two subsequent shocks at magnitude 5.0 and 6.2. The quake's epicentre was from the northern Thai city of Chiang Rai, north of Mae Sai and southeast of Kentung.

The 1979 Imperial Valley earthquake occurred at 16:16 Pacific Daylight Time (23:16 UTC) on 15 October just south of the Mexico–United States border. It affected Imperial Valley in Southern California and Mexicali Valley in northern Baja California. The earthquake had a relatively shallow hypocenter and caused property damage in the United States estimated at US$30 million. The irrigation systems in the Imperial Valley were badly affected, but no deaths occurred.

Eizō Nomura was the closest known survivor, being in the basement of a reinforced concrete building (it remained as the Rest House after the war) only from ground zero at the time of the attack. He died in 1982, aged 84. Akiko Takakura was among the closest survivors to the hypocenter of the blast. She was in the solidly- built Bank of Hiroshima only from ground-zero at the time of the attack.

Only one doctor, Terufumi Sasaki, remained on duty at the Red Cross Hospital. Nonetheless, by early afternoon the police and volunteers had established evacuation centres at hospitals, schools and tram stations, and a morgue was established in the Asano library. Most elements of the Japanese Second General Army headquarters were undergoing physical training on the grounds of Hiroshima Castle, barely from the hypocenter. The attack killed 3,243 troops on the parade ground.

Several of the northwest-southeast-trending faults converge in the Inter-Andean Valley where the 1949 Ambato earthquake took place. The hypocenter of the earthquake occurred beneath the surface, under a mountain from Ambato. Nearby faults ruptured, breaking rock strata and sending shock waves to the surface capable of bringing down entire buildings. Life reported that local seismologists first placed the earthquake's magnitude at 7.5, but the official measurement was later revised to 6.4 .

Seismic tomography is similar to medical x-ray computed tomography (CT scan) in that a computer processes receiver data to produce a 3D image, although CT scans use attenuation instead of traveltime difference. Seismic tomography has to deal with the analysis of curved ray paths which are reflected and refracted within the earth and potential uncertainty in the location of the earthquake hypocenter. CT scans use linear x-rays and a known source.

Established in 1955, and near to the hypocenter of the explosion, remnants of a concrete wall of Urakami Cathedral can still be seen. Urakami Cathedral was the grandest church in east Asia at the time. At the park's north end is the 10-meter-tall Peace Statue created by sculptor Seibo Kitamura of Nagasaki Prefecture. The statue's right hand points to the threat of nuclear weapons while the extended left hand symbolizes eternal peace.

The Osmussaar earthquake occurred on 25 October 1976 near the north tip of Osmussaar, an island close to the coast of Estonia. Its hypocenter was below ground level, and it was measured at 4.5–4.7 . The earthquake was the most powerful recorded in Estonia; it caused rockfall along the north and northeastern coasts, and some houses took structural damage. The earthquake was largely felt in surrounding areas like north Estonia, south Finland and Sweden.

The April 2015 Nepal earthquake (also known as the Gorkha earthquake) killed nearly 9,000 people and injured nearly 22,000. It occurred at on 25 April 2015, with a magnitude of 7.8Mw or 8.1Ms and a maximum Mercalli Intensity of VIII (Severe). Its epicenter was east of Gorkha District at Barpak, Gorkha, and its hypocenter was at a depth of approximately . It was the worst natural disaster to strike Nepal since the 1934 Nepal–Bihar earthquake.

An earthquake is caused by the release of stored elastic strain energy during rapid sliding along a fault. The sliding starts at some location and progress away from the hypocenter in each direction along the fault surface. The speed of the progression of this fault tear is slower than, and distinct from the speed of the resultant pressure and shear waves, with the pressure wave traveling faster than the shear wave. The pressure waves generate an abrupt shock.

The M8.0 mainshock ruptured along the Sagaing Segment of the Sagaing Fault with an epicenter south of the Singu Plateau at a depth of 15.0 kilometers. It had a rupture length of approximately 185 kilometres. A second shock of magnitude 7.8 came three minutes later and ruptured north of the first event for a length of 155 kilometers, its hypocenter was at a depth of 15.0 kilometers. A pressure ridge along the Sagaing Fault, obstructed by vegetation, outside Mandalay.

The 2011 Zumpango earthquake occurred at with a moment magnitude of 6.5 and a maximum Mercalli intensity of VII (Very strong). Its epicenter was located in the city Zumpango, Guerrero, roughly equidistant between the metropolitan areas of Mexico City and Acapulco. The quake was felt in Guerrero, Michoacán, Mexico State, Mexico City and Puebla. Multiple deaths and injuries resulted from the earthquake, although the effects were minimized because the hypocenter was relatively deep at 65 kilometers.

On July 23, 1746, an earthquake hit the town of Barga. On January 21, 1767, Fivizzano was struck again, as was Pontremoli on February 14, 1834. Fivizzano was struck again on October 15, 1939, but while the energy release of the quake was larger, the hypocenter was much deeper (between 20 and 26 kilometres, or 12 to 16 mi, down) and damage was significant, but limited. On October 25, 1957, Pontremoli and Borgotaro were struck again by a very powerful quake.

Strong ground motions damage buildings, sometimes bringing about collapse. Shaking of the ground decreases with distance from the release of energy, the hypocenter, or, more accurately expressed, from the entire area of rupture. To calculate the intensity of shaking at a given settlement, the computer looks up the attenuation (decrease in amplitude) for seismic waves that travel the distance to the settlement in question. Such calculations are similar to those made to assess the seismic hazard, part of the field of engineering seismology.

The Quake Markup Language (QuakeML) is a flexible, extensible and modular XML representation of seismological data (e.g. epicenter, hypocenter, magnitude) which is intended to cover a broad range of fields of application in modern seismology. The flexible approach of QuakeML allows further extensions of the standard in order to represent waveform data, macroseismic information, probability density functions, slip distributions, shake maps, and others. QuakeML is an open standard and is developed by a distributed team in a transparent collaborative manner.

Overlapped cyan circles indicate the locations of earthquakes that were associated with the Nazko swarm. More than 1,000 earthquakes were recorded by regional seismic networks within three weeks of October 20, 2007. Because the seismometers that recorded the Nazko swarm were more than away from where the earthquakes took place, the locations of the hypocenters were measured with poor resolution. Following the earthquake, five seismometers were placed by the Geological Survey of Canada from September 2007 to June 2008 close to the hypocenter.

The shock originated on the Calaveras Fault and ruptured an area of the fault for a length of about beginning at the hypocenter and extending southeast. There was no evidence of any surface rupture along the fault caused by the earthquake. David Oppenheimer, a seismologist at the United States Geological Survey (USGS), said that although the quake was felt as a strong jolt over a wide region, it was more significant because it caused stress changes in the Calaveras Fault and the nearby Hayward Fault.

The detonation happened at an altitude of . It was less powerful than the Fat Man, which was dropped on Nagasaki, but the damage and the number of victims at Hiroshima were much higher, as Hiroshima was on flat terrain, while the hypocenter of Nagasaki lay in a small valley. According to figures published in 1945, 66,000 people were killed as a direct result of the Hiroshima blast, and 69,000 were injured to varying degrees. Of those deaths, 20,000 were members of the Imperial Japanese Army.

When Castro told Frémont he would have to leave the country, the situation came close to war when he obstinately refused to leave and instead set up a base on Gavilán Peak, overlooking the town of San Juan. However, fighting was avoided and Frémont, grudgingly, withdrew. Recently, using old photographs and eyewitness accounts, researchers were able to estimate the location of the hypocenter of the 1906 San Francisco earthquake as offshore from San Francisco, or near the city of San Juan Bautista, confirming previous estimates.

The 1964 Baihe earthquake (), also known as the Great Baihe earthquake, measured 6.3 local magnitude, and occurred at 20:04 CST (UTC+8) on 18 January in Baihe Township of Tainan County (now part of Tainan City), Taiwan. The hypocenter of the earthquake was 20 kilometers deep. The earthquake killed 106 people, destroyed 10,924 buildings, and caused a great fire in Chiayi City. It was the sixth deadliest earthquake in 20th century Taiwan, and the third deadliest post-World War II, after the 921 earthquake and the 2016 Taiwan earthquake.

In the next section, visitors enter a room which shows Nagasaki just after the bombings. Included in this room is a water tank with contorted legs which was located at Keiho Middle School, approximately 800 m away from the hypocenter of the bombing. The section "Events leading up to the Nagasaki Atomic Bombiing" isolates historical events from contemporary biases. The permanent exhibition rooms display large materials exposed to the blast, as well as a replica of a sidewall of the Urakami Cathedral which was hit by the bomb.

Less than a month after the Turkish disaster, on September 7, 1999, at 2:56 pm local time, it was Athens' turn to be hit by a powerful, magnitude 5.9 earthquake. This was the most devastating and costly natural disaster to hit the country in 20 years. The tremor had a very shallow hypocenter and an epicenter close to the Athenian suburbs of Ano Liossia and Acharnes, just away from the downtown area. A total of 143 people lost their lives in the disaster while more than 12,000 were treated for injuries.

Some of the reinforced concrete buildings in Hiroshima had been very strongly constructed because of the earthquake danger in Japan, and their framework did not collapse even though they were fairly close to the blast center. Since the bomb detonated in the air, the blast was directed more downward than sideways, which was largely responsible for the survival of the Prefectural Industrial Promotional Hall, now commonly known as the Genbaku (A-bomb) dome. This building was designed and built by the Czech architect Jan Letzel, and was only from ground zero (the hypocenter).

People outside a hotel in Mexico City a few minutes after the earthquake According to the National Seismological Service (SSN) of Mexico, the epicenter was located in the Gulf of Tehuantepec, about southeast of Tonalá, Chiapas. The United States Geological Survey (USGS) reported that the epicenter was about southwest of Pijijiapan, Chiapas. The hypocenter was about underground, deeper than usual for a relatively new subduction zone. The SSN reported a measurement of M 8.2, while the USGS also reported a M 8.2 earthquake after correcting an earlier estimate of M 8.0.

Therefore, a longer route can take a shorter time. The travel time must be calculated very accurately in order to compute a precise hypocenter. Since P waves move at many kilometers per second, being off on travel-time calculation by even a half second can mean an error of many kilometers in terms of distance. In practice, P arrivals from many stations are used and the errors cancel out, so the computed epicenter is likely to be quite accurate, on the order of 10–50 km or so around the world.

Six three-axis accelerometers that were within captured the event, including two units that were close to the projection of the fault at the surface. Analysis of the data recorded by these devices revealed the distribution of slip, moment release over time, and the location of the maximum slip. The mechanism of the event was typical of the thrust system of the Himalayas, with maximum slip () occurring to the west and southwest of the hypocenter. Energy release began slowly and built to a crescendo four seconds after the initiation of the rupture.

The Pacific War lasted until September 1, 1945, when Japan surrendered in response to the American atomic bombings of Hiroshima and Nagasaki – among the most controversial acts in military history – and the Soviet entry into the Asian theater of war following the surrender of Germany. The official Instrument of Surrender was signed on September 2, and the United States subsequently occupied Japan in its entirety. The Fat Man mushroom cloud resulting from the nuclear explosion over Nagasaki rises 18 km (11 mi, 60,000 ft) into the air from the hypocenter.

In 1996, the Hiroshima Peace Memorial was acknowledged as a Unesco World Heritage Site. Originally completed in 1905, the building was known at the time of the Hiroshima atomic bomb explosion on August 6, 1945 as the Hiroshima Prefectural Industrial Promotion Hall. Although suffering considerable damage, it was the closest structure to the hypocenter of the explosion to withstand the blast without being leveled to the ground. It has been preserved in the condition it was in after the bombing to serve as a symbol of hope for world peace and nuclear disarmament.

The earthquake occurred at 16:09:37 UTC (23:09:37 local time) on 28 March 2005. The hypocenter was located below the surface of the Indian Ocean, where subduction is forcing the Indo-Australian Plate to the southwest under the Eurasian Plate's Sunda edge. The area is west of Sibolga, Sumatra, or northwest of Jakarta, approximately halfway between the islands of Nias and Simeulue. Seismic recordings give the earthquake a moment magnitude of about 8.6, and effects were felt as far away as Bangkok, Thailand, over away.

Much smaller waves, most detectable only in tide gauge recording systems, were recorded across the Indian Ocean; for example, a wave was recorded at Colombo, Sri Lanka. Tsunami warnings were issued by the Pacific Tsunami Warning Center, operated by the US National Oceanic and Atmospheric Administration (NOAA), and by the government of Thailand. There were initial concerns that a major tsunami could be generated, particularly travelling south from the event's hypocenter. Portions of Thailand's southern coast were evacuated as a precaution, and NOAA advised an evacuation of of coastline in Sumatra.

The Chino Hills earthquake was caused by oblique-slip faulting, with components of both thrust and sinistral strike-slip displacement. Preliminary reports cited the Whittier fault as the active cause, but the quake was later determined to have been generated by the "Yorba Linda trend," as identified by Caltech seismologist Egill Hauksson. Its epicenter was within of Chino Hills and its hypocenter was c. deep. Initial estimations of the moderate main shock reported it as magnitude 5.8, but this was later revised to magnitude 5.4 and in later months to a 5.5.

The A-Bomb Dome is the skeletal ruins of the former Hiroshima Prefectural Industrial Promotion Hall. It is the building closest to the hypocenter of the nuclear bomb that remained at least partially standing. It was left how it was after the bombing in memory of the casualties. The A-Bomb Dome, to which a sense of sacredness and transcendence has been attributed, is situated in a distant ceremonial view that is visible from the Peace Memorial Park’s central cenotaph. It is an officially designated site of memory for the nation’s and humanity’s collectively shared heritage of catastrophe.

A 9.0-magnitude megathrust earthquake occurred off the coast of Japan on 11 March 2011. The epicenter was off the east coast of the Oshika Peninsula of Tōhoku near Sendai, with the hypocenter at a depth of . The earthquake triggered extremely destructive tsunami waves of up to that struck Japan minutes after the quake, in some cases traveling up to inland, with smaller waves reaching many other countries after several hours. Tsunami warnings were issued and evacuations ordered along Japan's Pacific coast and at least 20 other countries, including the entire Pacific coast of North America and South America.

The 2018 Oaxaca earthquake occurred on February 16, 2018 at 17:39 local time (23:39 UTC) in the Sierra Madre del Sur in Oaxaca state in Southern Mexico. It had a magnitude of 7.2 on the moment magnitude scale and a maximum felt intensity of VII (very strong) on the Mercalli intensity scale. The hypocenter was located at a depth of 24.6 km and approximately 37 km northeast of Pinotepa de Don Luis. There were only two reports of injuries from the earthquake, but later a military helicopter surveying the damage crashed and killed 14 people.

The epicenter is directly above the earthquake's hypocenter (also called the focus). In most earthquakes, the epicenter is the point where the greatest damage takes place, but the length of the subsurface fault rupture may indeed be a long one, and damage can be spread on the surface across the entire rupture zone. As an example, in the magnitude 7.9 2002 Denali earthquake in Alaska, the epicenter was at the western end of the rupture, but the greatest damage was about away at the eastern end. Focal depths of earthquakes occurring in continental crust mostly range from .

The tremor occurred at 11:57am KST (2:57am UTC), and the USGS said the hypocenter of the event was only one kilometer deep. Later, the Geophysical Service of the Russian Academy of Sciences assures the residents in the Russian Far East that the nuclear blast did not trigger any seismic events and underground tremors at 16:00 local time on 12 February 2013 in the area and thus the North Korea's nuclear test does not pose danger to the residents there. The China Earthquake Networks Center (Abbreviation: CENC; ) also reported this event, putting the magnitude at Ms 4.9.

Dr. Terufumi Sasaki was a surgeon at the Red Cross hospital in Hiroshima in 1945 and was personally situated 1,650 yards from the hypocenter of the Little Boy explosion. Twenty-five years old that year, out of an initial 30 interviewed,Yale News Chronicles of disaster: Hiroshima in the Yale University Library archives. 2014 he became one of the six central biopics found in the 1946 book Hiroshima by John Hersey. He lived at his family home in Mukaihara district prior to the detonation and practiced medicine in communities with poor health care without a permit.

Location of 1994 earthquake Located on the southeastern edge of the New Madrid Seismic Zone, the settlement of Randolph is situated in an area with a high earthquake risk. Between 1974 and 2004, ten earthquakes have been recorded in a radius of around Randolph. The magnitude of the temblors ranged from 1.5 to 3.2 on the Richter scale. The hypocenter depth ranged from to .Center for Earthquake Research and Information (CERI) - New Madrid Earthquake Catalog Search Results of a radial search centered at latitude 35.5166 and longitude -89.8886 with a search radius of 16 km (ca.

The 2005 northern Peru earthquake occurred on September 25 at 20:56 local time (01:56 UTC) with a magnitude of 7.5. It resulted in the deaths of at least five people. The epicenter was located about northeast of the jungle city of Moyobamba in the San Martín Region of Peru, and the earthquake struck an area about north of Lima. With its hypocenter located roughly below the surface, the quake extended itself below the Andes and was felt in a large area, including the Peruvian coastal regions and as far away as Bogotá, Colombia, as well as most of Ecuador and western Brazil.

Trucks and trains brought in relief supplies and evacuated survivors from the city. Twelve American airmen were imprisoned at the Chugoku Military Police Headquarters, about from the hypocenter of the blast. Most died instantly, although two were reported to have been executed by their captors, and two prisoners badly injured by the bombing were left next to the Aioi Bridge by the Kempei Tai, where they were stoned to death. Eight U.S. prisoners of war killed as part of the medical experiments program at Kyushu University were falsely reported by Japanese authorities as having been killed in the atomic blast as part of an attempted cover up.

While estimates, as to yield, are still uncertain, with reports ranging from 3 to 20 kilotons, the stronger tremor indicates a significantly larger yield than the 2006 test. On 12 February 2013, North Korean state media announced it had conducted an underground nuclear test, its third in seven years. A tremor that exhibited a nuclear bomb signature with an initial magnitude 4.9 (later revised to 5.1) was detected by both Comprehensive Nuclear-Test-Ban Treaty Organization Preparatory Commission (CTBTO) and the United States Geological Survey (USGS). The tremor occurred at 11:57 local time (02:57 UTC) and the USGS said the hypocenter of the event was only one kilometer deep.

The 2003 San Simeon earthquake struck at 11:15 PST (19:15 UTC) on December 22 on the Central Coast of California, about northeast of San Simeon. Probably centered in the Oceanic fault zone within the Santa Lucia Mountains, it was caused by thrust faulting and the rupture propagated southeast from the hypocenter for 12 miles (19 km). The most violent ground movement was within 50 miles of the epicenter, though the earthquake was felt as far away as Los Angeles. With a moment magnitude of 6.6, it was the most destructive earthquake to hit the United States since the Northridge quake of 1994.

The 1999 quake was the most devastating and costly natural disaster to hit the country in nearly 20 years. The last major earthquake to hit Athens took place on February 24, 1981, near the Alkyonides Islands of the Corinthian Gulf, some 87 km to the west of the Greek capital. Registering a moment magnitude of 6.7, the 1981 earthquake had resulted in the deaths of 20 people and considerable and widespread structural damage in the city of Corinth, nearby towns and sections of Athens' western suburbs. Apart from the proximity of the epicenter to the Athens Metropolitan Area, this quake also featured a very shallow hypocenter combined with unusually high ground accelerations.

In relation to nuclear explosions and other large bombs, ground zero (also called surface zero) is the point on the Earth's surface closest to a detonation.Nuclear Matters: A Practical Guide, Appendix B In the case of an explosion above the ground, ground zero is the point on the ground directly below the nuclear detonation and is sometimes called the hypocenter (from Greek ὑπο- ("under-") and center). Generally, the term "ground zero" is also used in relation to earthquakes, epidemics, and other disasters to mark the point of the most severe damage or destruction. The term is distinguished from the term zero point in that the latter can also be located in the air, underground, or underwater.

During an earthquake, seismic waves propagate in all directions from the hypocenter. Seismic shadowing occurs on the opposite side of the Earth from the earthquake epicenter because the planet's liquid outer core refracts the longitudinal or compressional (P-waves) while it absorbs the transverse or shear waves (S-waves). Outside the seismic shadow zone, both types of wave can be detected but, because of their different velocities and paths through the Earth, they arrive at different times. By measuring the time difference on any seismograph and the distance on a travel-time graph on which the P-wave and S-wave have the same separation, geologists can calculate the distance to the quake's epicenter.

On August 6, 1945, Shima Hospital was completely destroyed by the atomic bombing of Hiroshima; the atomic bomb detonated right above the building and the blast was directed downwards. Because the epicenter of the atomic bombing of Hiroshima is over the hospital, the hypocenter, or ground zero, is the hospital itself."The epicenters of the atomic bombs: 2", HH Hubbell, TD Jones, JS Cheka, 1969 All the medical staff and the inpatients who were in Shima Hospital, about 80, died instantly. At the time of the detonation, Kaoru Shima was away from Hiroshima city, as he had gone to assist a colleague with a difficult operation at a hospital in a nearby town.

Due to its stone and steel construction, the building was one of the few structures left standing near the bomb’s hypocenter. Soon commonly called the Genbaku ("A-Bomb") Dome, due to the exposed metal dome framework at its apex, the structure was scheduled to be demolished with the rest of the ruins, but the majority of the building was intact, delaying the demolition plans. The Dome became a subject of controversy, with some locals wanting it torn down, while others wanted to preserve it as a memorial of the bombing and a symbol of peace.Hiroshima Peace Museum Ultimately, when the reconstruction of Hiroshima began, the skeletal remains of the building were preserved.

The dominant effects of a nuclear weapon (the blast and thermal radiation) are the same physical damage mechanisms as conventional explosives, but the energy produced by a nuclear explosive is millions of times more per gram and the temperatures reached are in the tens of megakelvin. Nuclear weapons are quite different from conventional weapons because of the huge amount of explosive energy they can put out and the different kinds of effects they make, like high temperatures and nuclear radiation. The devastating impact of the explosion does not stop after the initial blast, as with conventional explosives. A cloud of nuclear radiation travels from the hypocenter of the explosion, causing an impact to life forms even after the heat waves have ceased.

On 2 April 2007 at 07:39:56 local time (UTC+11) an earthquake with magnitude 8.1 occurred at hypocenter S8.453 E156.957, 349 kilometres (217 miles) northwest of the island's capital, Honiara and south- east of the capital of Western Province, Gizo, at a depth of 10 km (6.2 miles)."Solomon Islands earthquake and tsunami", Breaking Legal News – International, 4 March 2007 More than 44 aftershocks with magnitude 5.0 or greater occurred up until 22:00:00 UTC, Wednesday, 4 April 2007. A tsunami followed killing at least 52 people, destroying more than 900 homes and leaving thousands of people homeless."Aid reaches tsunami-hit Solomons", BBC News, 3 April 2007 Land upthrust extended the shoreline of one island, Ranongga, by up to 70 metres (230 ft) exposing many once pristine coral reefs.

The Fat Man mushroom cloud resulting from the nuclear explosion over Nagasaki rises into the air from the hypocenter. The debate over the atomic bombings of Hiroshima and Nagasaki concerns the ethical, legal, and military controversies surrounding the atomic bombings of Hiroshima and Nagasaki on 6 August and 9 August 1945 at the close of World War II (1939–45). The Soviet Union declared war on Japan an hour before 9 August and invaded Manchuria at one minute past midnight; Japan surrendered on 15 August. On 26 July 1945, United States President Harry S. Truman, United Kingdom Prime Minister Winston Churchill, and Chairman of the Chinese Nationalist Government Chiang Kai-shek issued the Potsdam Declaration, which outlined the terms of surrender for the Empire of Japan as agreed upon at the Potsdam Conference.

The most well known of these was Midori Naka, some from the hypocenter at Hiroshima, who would travel to Tokyo and then with her death on August 24, 1945 was to be the first death officially certified as a result of radiation poisoning, or as it was referred to by many, "atomic bomb disease". It was unappreciated at the time but the average radiation dose that will kill approximately 50 percent of adults, the LD50, was approximately halved, that is, smaller doses were made more lethal, when the individual experienced concurrent blast or burn polytraumatic injuries. Conventional skin injuries that cover a large area frequently result in bacterial infection; the risk of sepsis and death is increased when a usually non-lethal radiation dose moderately suppresses the white blood cell count.

Cancers do not immediately emerge after exposure to radiation; instead, radiation-induced cancer has a minimum latency period of some five years and above, and leukemia some two years and above, peaking around six to eight years later. Dr Jarrett Foley published the first major reports on the significant increased incidence of the latter among survivors. Almost all cases of leukemia over the following 50 years were in people exposed to more than 1Gy. In a strictly dependent manner dependent on their distance from the hypocenter, in the 1987 Life Span Study, conducted by the Radiation Effects Research Foundation, a statistical excess of 507 cancers, of undefined lethality, were observed in 79,972 hibakusha who had still been living between 1958–1987 and who took part in the study.

To elucidate the effects on lying flat on the ground in attenuating a weapons blast, Miyoko Matsubara, one of the Hiroshima maidens, when recounting the bombing in an interview in 1999, said that she was outdoors and less than 1 mile from the hypocenter of the Little Boy bomb. Upon observing the nuclear weapons silent flash she quickly lay flat on the ground, while those who were standing directly next to her, and her other fellow students, had simply disappeared from her sight when the blast wave arrived and blew them away. Position of the body can have a considerable influence in protection from blast effects. Lying prone on the ground will often materially lessen direct blast effects because of the protective defilade effects of irregularities in the ground surface.

The JMA has its own 624 observation stations across the country that set up at intervals of 20 km approximately in order to measure seismic intensity of earthquakes precisely. The agency also utilize about 2,900 more seismographs owned by the National Research Institute for Earth Science and Disaster Prevention (NIED) and local governments. A 24-hour office has been housed within the JMA headquarters in Tokyo, for monitoring and tracking seismic events in the vicinity of Japan to collect and process their data, which issues observed earthquake's information on its hypocenter, magnitude, seismic intensity and possibility of tsunami occurrence after quakes quickly to the public through the Earthquake Phenomena Observation System (EPOS). The Earthquake Early Warning (EEW) system began to work fully for the general public on October 1, 2007.

Also, the lake's long axis points to the hypocenter of the Tunguska explosion, about 7.0 km away. Magnetic readings also indicate a possible meter-sized chunk of rock below the lake's deepest point, which may be a fragment of the colliding body. In 2008, a BBC News story on the 100th anniversary of the Tunguska Event mentioned that researchers at Imperial College London had pointed out that many of the trees surrounding the lake are older than 100 years, which suggests that the lake could not have been created by an impact in 1908. The researchers also pointed out other problems, including the morphology of the lake and the surrounding terrain, the lack of impactor debris and ejecta, noting that the characteristics of the impactor required by the impact theory are inconsistent with existing models of the known features of the event.

William Laurence, an embedded reporter with the Manhattan Project, reported that "Zero" was "the code name given to the spot chosen for the [Trinity] test" in 1945.William L. Laurence, Dawn over Zero (London: Museum Press, 1947), 4. The Oxford English Dictionary, citing the use of the term in a 1946 New York Times report on the destroyed city of Hiroshima, defines ground zero as "that part of the ground situated immediately under an exploding bomb, especially an atomic one." The term was military slang, used at the Trinity site where the weapon tower for the first nuclear weapon was at "point zero", and moved into general use very shortly after the end of World War II. At Hiroshima, the hypocenter of the attack was Shima Hospital, approximately away from the intended aiming point at Aioi Bridge.

A few months after he was put in charge of fast neutron research, Berkeley physicist J. Robert Oppenheimer convened a conference on the topic of nuclear weapon design. Leó Szilárd driving force to create the Manhattan Project authored the Einstein–Szilárd letter signed by Albert Einstein Albert Einstein (left) with J. Robert Oppenheimer (right) working on the Manhattan Project The Fat Man mushroom cloud resulting from the nuclear explosion over Nagasaki rises 18 km (11 mi, 60,000 ft) into the air from the hypocenter resulting in the surrender of Japan and United States' victory over Japan in World War II. By executive order of president Harry S. Truman, the U.S. dropped the nuclear weapon "Little Boy" on the city of Hiroshima on Monday, August 6, 1945, page on Hiroshima casualties.Adams, S. & Crawford, A.. 2000. World War II. First edition.

According to the USGS: > The Mw 6.8 Honshu earthquake of June 13th 2008 occurred in a region of > convergence between the Pacific Plate and the Okhotsk section of the North > American Plate in northern Japan, where the Pacific plate is moving west- > northwest with respect to North America at a rate of approximately 8.3 > cm/yr. The hypocenter of the earthquake indicates shallow thrusting motion > in the upper (Okhotsk) plate, above the subducting Pacific plate, which lies > at approximately 80 km depth at this location. > The earthquake occurred in a region of upper-plate contraction, probably > within the complicated tectonics of the Ou Backbone Range, known to have > hosted several large earthquakes in historic times. The largest of these > events occurred in 1896, approximately 70km north of the June 13th event, > and killed over 200 people in the local area.

The mushroom cloud of the atomic bomb dropped on Nagasaki, Japan on August 9, 1945, rose over above the bomb's hypocenter. An estimated 39,000 people were killed by the atomic bomb,The Atomic Bombings of Hiroshima and Nagasaki. atomicarchive.com of whom 23,145–28,113 were Japanese factory workers, 2,000 were Korean slave laborers, and 150 were Japanese combatants. One class of nuclear weapon, a fission bomb (not to be confused with the fusion bomb), otherwise known as an atomic bomb or atom bomb, is a fission reactor designed to liberate as much energy as possible as rapidly as possible, before the released energy causes the reactor to explode (and the chain reaction to stop). Development of nuclear weapons was the motivation behind early research into nuclear fission which the Manhattan Project during World War II (September 1, 1939 – September 2, 1945) carried out most of the early scientific work on fission chain reactions, culminating in the three events involving fission bombs that occurred during the war.

Historically, several significant earthquakes have occurred along the southern coast of Mexico. In 1932, a M 8.4 megathrust earthquake struck in the region of Jalisco, several hundred kilometers to the northwest of the Oaxaca event. On October 9, 1995, a M 8.0 earthquake struck in the Colima-Jalisco region, resulting in at least 49 fatalities and leaving 1,000 people homeless. The deadliest nearby earthquake occurred on September 19, 1985, in the Michoacán region 500 km to the northwest of the February 16th event. This M 8.0 earthquake resulted in at least 9,500 fatalities, injured about 30,000 people, and left 100,000 people homeless. In 2003, a M 7.6 earthquake in Colima, Mexico, resulted in 29 fatalities, destroyed more than 2,000 homes and left more than 10,000 people homeless. In March 2012, a M 7.4 earthquake 60 km to the northwest of the February 16, 2018 event killed 2 and injured 11 in the Oaxaca region. The hypocenter of the M 8.2 earthquake off the shore of Chiapas in September 2017 was located 440 km southwest of this earthquake.

Soviet military planners assumed they could win a nuclear war.Why the Soviet Union thinks it can fight and win a Nuclear War, Richard Pipes, Professor of History Harvard University 1977 Therefore, they expected a large-scale nuclear exchange, followed by a "conventional war" which itself would involve heavy use of tactical nuclear weapons. American doctrine rather assumed that Soviet doctrine was similar, with the mutual in mutually assured destruction necessarily requiring that the other side see things in much the same way, rather than believing—as the Soviets did—that they could fight a large-scale, "combined nuclear and conventional" war. In accordance with their doctrine, the Soviet Union conducted large-scale military exercises to explore the possibility of defensive and offensive warfare during a nuclear war. The exercise, under the code name of "Snowball", involved the detonation of a nuclear bomb about twice as powerful as that which fell on Nagasaki and an army of approximately 45,000 soldiers on maneuvers through the hypocenter immediately after the blast.Viktor Suvorov, Shadow of Victory (), Donetsk, 2003, , pages 353–375.

Silent film footage taken in Hiroshima in March 1946 showing survivors with severe burns and keloid scars. Survivors were asked to stand in the orientation they were in at the time of the flash, to document and convey the line-of-sight nature of flash burns, and to show that, much like a sunburn, thick clothing and fabric offered protection in many cases. The sometimes extensive burn scar contracture is not unusual, being common to all second- and third-degree burns when they cover a large area of skin. An estimated 90,000 to 140,000 people in Hiroshima (up to 39 percent of the population) and 60,000 to 80,000 people in Nagasaki (up to 32 percent of the population) died in 1945, though the number which died immediately as a result of exposure to the blast, heat, or due to radiation, is unknown. One Atomic Bomb Casualty Commission report discusses 6,882 people examined in Hiroshima, and 6,621 people examined in Nagasaki, who were largely within from the hypocenter, who suffered injuries from the blast and heat but died from complications frequently compounded by acute radiation syndrome (ARS), all within about 20 to 30 days.

He also studied the longevity of the children who survived the bombings of Hiroshima and Nagasaki, reporting that between 90 and 95 percent were still living 50 years later. While The National Academy of Sciences raised the possibility that Neel's procedure did not filter the Kure population for possible radiation exposure which could bias the results. Overall, a statistically insignificant increase in birth defects occurred directly after the bombings of Nagasaki and Hiroshima when the cities were taken as wholes, in terms of distance from the hypocenters however, Neel and others noted that in approximately 50 humans who were of an early gestational age at the time of the bombing and who were all within about from the hypocenter, an increase in microencephaly and anencephaly was observed upon birth, with the incidence of these two particular malformations being nearly 3 times what was to be expected when compared to the control group in Kure, were approximately 20 cases were observed in a similar sample size. In 1985, Johns Hopkins University geneticist James F. Crow examined Neel's research and confirmed that the number of birth defects was not significantly higher in Hiroshima and Nagasaki.

According to the JMA , reasons for the underestimation include a saturated magnitude scale when using maximum amplitude as input, failure to fully take into account the area of the hypocenter, and the initial amplitude of the earthquake being less than that which would be predicted by an empirical relationship.干場充之 (2011) 経験則からのずれ ―はじめの数秒と強震動：τc, Pd，スペクトル，簡易震源域推定方法― 日本地球惑星科学連合 2011年 MIS036-P67緊急地震速報と観測された震度の特徴 JMA 日本地球惑星連合 2011年予稿集 There were also cases where large differences between estimated intensities by the Earthquake Early Warning system and the actual intensities occurred in the aftershocks and triggered earthquakes. Such discrepancies in the warning were attributed by the JMA to the system's inability to distinguish between two different earthquakes that happened at around same time, as well as to the reduced number of reporting seismometers due to power outages and connection fails. The system's software was subsequently modified to handle this kind of situation.