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The '''1976 Tangshan earthquake''', also known as '''Great Tangshan earthquake''',<ref>So-called by numerous sources, of which the voluminous work edited by {{Harvtxt|Housner|He|2002}} is the most notable.</ref> was a natural disaster resulting from a {{m|magnitude}} 7.6 earthquake that hit the region around [[Tangshan]], [[Hebei]], [[People's Republic of China]] on 28 July 1976, at 3:42 in the morning. In minutes the city of Tangshan, an industrial city with approximately one million inhabitants, ceased to exist. Eighty-five percent of the buildings in the city collapsed or were unusable, all services failed, and most of the highway and railway bridges collapsed or were seriously damaged.<ref>{{Harvnb|Housner|He|2002|loc=Prologue}}.</ref> This earthquake is regarded as one of the most damaging in modern history. At least 242,000 people died (some have said three times that), making this the third (or possibly second) deadliest earthquake in recorded history.<ref>See the [[#Death toll]] section for the various fatality figures.</ref>
The '''1976 Tangshan earthquake''', also known as '''Great Tangshan earthquake''',<ref>So-called by numerous sources, of which the voluminous work edited by {{Harvtxt|Housner|He|2002}} is the most notable.</ref> was a natural disaster resulting from a {{m|magnitude}} 7.6 earthquake that hit the region around [[Tangshan]], [[Hebei]], [[People's Republic of China]] on 28 July 1976, at 3:42 in the morning. In minutes the city of Tangshan, an industrial city with approximately one million inhabitants, was nearly completely destroyed. Eighty-five percent of the buildings in the city collapsed or were unusable, all services failed, and most of the highway and railway bridges collapsed or were seriously damaged.<ref>{{Harvnb|Housner|He|2002|loc=Prologue}}.</ref> At least 242,000 people died (some have said three times that), making this the third (or possibly second) deadliest earthquake in recorded history.<ref>See the [[#Death toll]] section for the various fatality figures.</ref>


Tangshan was the most notable of several disasters in 1976, which in Chinese tradition might signal that the government had [[Mandate_of_Heaven|lost political legitimacy.]]<ref>{{Harvnb|Yeoh|2010|p=273}}; {{Harvnb|Press|Bullock|Hamilton|Brace|1975|p=879}}. Yeoh called the Tangshan earthquake "[p]robably one of the deadliest wraths of nature in modern times".</ref> The Tangshan earthquake also came without warning, undermining a key tenet of Maoist ideology, that earthquakes could be predicted.<ref>{{Harvnb|Cha|1976|p=7}}.</ref> Nonetheless, the government's response showed that it was prepared and competent to quickly provide relief.<ref>{{Harvnb|Raleigh|Bennett|Craig|Hanks|1977|p=259}}.</ref>
Tangshan was the most notable of several disasters in 1976, which in Chinese tradition might signal that the government had [[Mandate_of_Heaven|lost political legitimacy.]]<ref>{{Harvnb|Yeoh|2010|p=273}}; {{Harvnb|Press|Bullock|Hamilton|Brace|1975|p=879}}. Yeoh called the Tangshan earthquake "[p]robably one of the deadliest wraths of nature in modern times".</ref> The Tangshan earthquake also came without warning, undermining a key tenet of Maoist ideology, that earthquakes could be predicted.<ref>{{Harvnb|Cha|1976|p=7}}.</ref> Nonetheless, the government's response showed that it was prepared and competent to quickly provide relief.<ref>{{Harvnb|Raleigh|Bennett|Craig|Hanks|1977|p=259}}.</ref>

Revision as of 23:49, 27 February 2020

Tangshan earthquake
UTC timeDoublet earthquake:    
 A: 1976-07-27 19:42:55
 B: 1976-07-28 10:45:36
ISC event 
 A: 711732
 B: 711773
USGS-ANSS 
 A: ComCat
 B: ComCat
Local date28 July 1976
Local timePeking time:
 A: 03:43
 B: 18:45
Magnitude 
 A: 7.6 Mw; 7.6 Ms[1]
 B: 7.0 Mw; 7.4 Ms[2]
DepthA: 12.2 km[3]
B: 16.7 km[4]
Epicenter39°38′N 118°06′E / 39.63°N 118.10°E / 39.63; 118.10 39°43′N 118°26′E / 39.72°N 118.44°E / 39.72; 118.44
Areas affectedHebei Province, People's Republic of China
Total damageCMY 10 billion
Max. intensityXI (Extreme)
Casualties242,419[5]

The 1976 Tangshan earthquake, also known as Great Tangshan earthquake,[6] was a natural disaster resulting from a magnitude 7.6 earthquake that hit the region around Tangshan, Hebei, People's Republic of China on 28 July 1976, at 3:42 in the morning. In minutes the city of Tangshan, an industrial city with approximately one million inhabitants, was nearly completely destroyed. Eighty-five percent of the buildings in the city collapsed or were unusable, all services failed, and most of the highway and railway bridges collapsed or were seriously damaged.[7] At least 242,000 people died (some have said three times that), making this the third (or possibly second) deadliest earthquake in recorded history.[8]

Tangshan was the most notable of several disasters in 1976, which in Chinese tradition might signal that the government had lost political legitimacy.[9] The Tangshan earthquake also came without warning, undermining a key tenet of Maoist ideology, that earthquakes could be predicted.[10] Nonetheless, the government's response showed that it was prepared and competent to quickly provide relief.[11]

The earthquakes

The Tangshan earthquake was complex, with multiple events. There were two main shocks. The first struck at 3:42:56 in the morning (local time), approximately 12 km under the southern part of Tangshan.[12] The magnitude was initially estimated at around 8.1, subsequently recalculated to be 7.6 on the standard Mw scale.[13] However, that scale measures only the total energy released by an earthquake, and earthquakes vary in how much of that energy is converted to seismic shaking. The Tangshan quake, being relatively shallow, converted much of its energy to surface shaking, and on the Ms (surface magnitude) scale it also measured 7.6. (7.8 on the Chinese surface magnitude scale.[14]) This "occurred on a near vertical right-lateral strike-slip fault, striking N40°E",[15] the block on the southeast side sliding about three meters to the southwest.[16] This resulted from tectonic compression on a nearly west-east axis.[17] Surface rupturing occurred in five en echelon segments extending eight kilometers through the center of Tangshan.[18]

The second main shock, with a magnitude 7.0 Mw , or 7.4 Ms , struck that afternoon at 18:45 near Luanhsien (Luanxian), about 70 km to the east-northeast ("B" on the intensity map in the next section), just south of the northeastern end of the Tangshan fault.[19] This occurred in a zone of north-northwest striking conjugate faults that cut across the north end of the Tangshan fault. The left-lateral motion here, along with the right-lateral motion on the Tangshan fault, suggests that as the crustal blocks to the west and east are compressed together the block between these two earthquakes is being squeezed out to the south.

A long sequence of aftershocks followed, with twelve of magnitude 6 or greater.[20] The first of these struck just three and a half hours after the initial shock, at 7:17, at the southern end of Tangshan fault, near Ninghe ("C" on the map in the section below),[21] with a magnitude of 6.2 Ms . Another significant aftershock (Ms 6.9) occurred in November near Ninghe. Most aftershocks occurred between these end points, in a zone 140 km long and about 50 km wide.[22] Many buildings were further damaged by the aftershocks.[23]

Damage

Extent of significant shaking
Map
About OpenStreetMaps
Maps: terms of use
75km
50miles
none
VIII
VII
VI
C
B
A
Tangshan
Sea of Bohai
Qinglong
Zunhua
Changli
Ninghe
Qinhuangdao
Tianjin
Beijing
Approximate extent of different intensities of shaking (isoseismals). Heaviest damage was within the dark brown line (intensity VII and greater). Diamonds locate the two principal shocks (A and B), and the area of several M > 6 aftershocks near Ninghe (C).

The damage done by an earthquake depends primarily on two factors. First, the intensity of shaking, which depends mainly on the magnitude of the earthquake rupture, the distance from the epicenter, and the nature of the local soil and topography, with soft soils (e.g., sediments and fill) more likely to amplify the intensity and duration of the shaking.[24] Second, the design and construction of the structures being shaken, with houses built of adobe or stone, wooden houses without a well-built frame, and unreinforced masonry construction being especially vulnerable.[25] The seismic risk had been greatly underestimated and almost all buildings and structures were designed and built without seismic considerations.[26] As a result, Tangshan was "mainly a city of unreinforced brick buildings",[27] sitting right on top of a major earthquake.

The power (magnitude) of the Tangshan earthquake is indicated by the extent of where it was felt: up to 1,100 km (680 miles) away, across most of northeastern China, and even in Mongolia and Korea.[28] In and around Beijing, 140 km (87 miles) from the epicenter, the shaking reached an intensity of VI on the Chinese intensity scale (similar to the Modified Mercalli Intensity Scale), with nearly 10% of all buildings damaged,[29] and at least 50 people died.

The economic loss totaled to 10 billion yuan.[30]

Intensity XI and X zone

Tangshan earthquake site

The rupture occurred under the southern part of the city, and propagated northeastward on a fault that runs through the middle of the city. The maximum intensity was "XI" (eleven) on the 12-degree Chinese scale. Nearly every building and structure in the city collapsed, wholly or partially, infrastructure was severely damaged, and essential services such as electric power, water supply, and communications were entirely knocked out. This area of maximum damage – the meizoseismal area – was approximately 10.5 kilometres (6.5 miles) long and from 3.5 to 5.5 km wide, centered roughly along the railway.[31]

The area of intensity X shaking – where only new, one-story brick buildings were merely "damaged or slightly damaged", the rest being severely damaged or worse – was 36 km long and 15 km across.[32] In this "high intensity" zone (intensity X and XI, within the red contour on the map) 20 highway bridges and five railway bridges cross the Douhe River in Tangshan; only six survived with only minor damage.[33]

Intensity IX and VIII zone

Shaking of intensity IX (or greater) occurred in a zone roughly 78 km (48 mi) long and 42 km (26 mi) (about 1800 km2, inner orange contour on the map), and also around the aftershocks at Luanxian and Ninghe. In this zone most buildings classified as Class III (well-built buildings of wood, masonry, or reinforced concrete[34]) survived,[35] but many Class II buildings (typically old wood-frame buildings lacking a well-built frame, and quite common outside of the cities) were destroyed, while a majority of Class I buildings (built of adobe or stone) were destroyed.

Further out (to the outer orange contour), and around the city of Tianjin and a few isolated patches, intensity VIII shaking mostly affected Class I buildings (more than half destroyed), bridges, and tall brick chimneys. Railway track was also subject to bending or displacement, depending on soil conditions.[36]

Intensity VII zone

The zone of intensity VII shaking – inside the dark brown contour – marks the extent of moderate damage, where many Class I structures (of weak design or construction) were damaged but only "few"—between 10% and 30%—were destroyed, and only a "few" Class two buildings damaged. This ellipsoid zone extended about 75 km north and south of Tangshan and 120 km east and west, from about 25 km short of Beijing to short of Qinhuangdao City (which had anomalously higher shaking), and from the Sea of Bohai in the south and southwest to just north of Zunhua. The north-south shortening of this zone is attributed to buttressing by the bedrock of the Yanshin mountains.

Significant damage occurred beyond this in the VI zone, but (like in Beijing) affected less than 10% of the buildings, or occurred in small localized areas.[37]

Coal mines

Mining coal is Tangshan's principal industry, and when the quake struck around 10,000 miners were underground. For the most part the mine roadways (tunnels) were not seriously damaged, but with the loss of electrical power there was no illumination (aside from headlamps), no ventilation, and no working lifts.[38] It is reported that most miners escaped within hours, but that some did not reach the surface until two weeks later.[39]

Most of the damage to the vertical shafts occurred within the first 50 meters, where they pass through the water-bearing alluvium. In many cases the concrete liner built to keep out the water cracked (particularly where not built properly), allowing a much greater inflow of water. Coupled with damage to the underground drainage system and lack of power to drive the pumps, many of the various mines flooded.[40]

Some electrical power to the mines was restored in three days, and some coal production resumed within ten days.[41] However, de-watering, overhauling of flooded electrical equipment, and rebuilding of surface buildings and structures continued for a year and a half; the pre-earthquake level of production was not reached until the end of 1977.[42]

Railways

The Beijing–Shanhaiguan Railway (built in 1887) is a double-track Class I trunk line that runs from Beijing southeast to Tianjin and Tanggu, then turns northeast to cross the Yongdingxin River and its estuary to run to Ninghe and then Tangshan. From Tangshan it continues northeast and then east to Chengli, and then to Qinhuangdao and Shanhaiguan. This is the principal connection of Beijing, Tianjin, and Tangshan to the seaports, and to Northeast China. The Tongxian to Tuozitou (within modern-day Luan County) Railway (built in 1976) is a single-track Class I trunk line that runs east from the eastern outskirts of Beijing to where it meets the Beijing to Shanhaiguan line northeast of Tangshan (near the epicenter of the M 7.1 quake).[43] All of this was built "with no consideration for earthquake resistant design",[44] although some "earthquake resistance measures" for large and medium bridges were applied following the 1975 Haicheng earthquake.

These vital arteries (and other railways and branch lines) were seriously damaged by the earthquakes, mainly in the areas of intensity IX or greater shaking.[45] (This includes a large area around Tangshan quake, and areas around Ninghe and Luanhsien following the M 6.9 and M 7.4 aftershocks.) At the time of the main quake there were 28 freight trains and seven passenger trains traveling on the Beijing–Shanhaiguan line in the affected area; seven freight trains and two passenger trains derailed due to derangement of the rails,[46] mostly south of Tangshan[47] where the line was built on loose alluvium, diluvium, and occasional stretches of loose sand.[48] In many of these cases – and also similar cases northeast of Tangshan, and on the Tongxian–Tuozitou line east of Fengrun – the railway embankment slumped due to weak soils. In other cases the embankment held, but transverse compression of the rails caused them to buckle.[49]

Railway operations were further impaired by the loss of communications (including signalling) and water supply (for the steam locomotives), in both cases due mainly to collapse of buildings and loss of electrical power.[50] However, the most serious damage, taking the most manpower and longest time to repair, was that involving bridges.[51] Most difficult was where soft or liquefied soil allowed the bank to slide into the river, shifting the abutments. A more frequent problem was where an approach embankment subsided, typically leaving the rails suspended from the abutment. There were numerous cases where concrete piers and abutments were damaged due to inadequate design and construction; bridges that were strengthened following the Haicheng earthquake survived with only slight damage.[52]

It was observed that at intensity VII and above damage to the roadbed was correlated mainly with loose soil and a high water table. Conversely, bridges and rails in Tangshan City, built on dense soil with a deep water table, were largely undamaged even though subject to intensity XI shaking.[53]

Over forty-two thousand people were mobilized to quickly effect emergency repair of the railways.[54] The Tongxian-Tuozitou line was opened for traffic on 3 August, single track of the Beijing-Shanhaiguan line opened on 7 August, and both tracks on 10 August, albeit at restricted speeds over temporary bridges and at other places where repairs were not yet complete.[55]

Death toll

A Tangshan earthquake memorial in Tianjin

Estimates of the number of deaths due to the Tangshan earthquake have varied widely, and generally lack a clear authoritative basis.

Early reports

One of the earliest reports outside of China came on the 28th[56] from the International Tsunami Information Center, reporting that a "violent" earthquake, initially estimated at about magnitude 8.1, had struck "in the vicinity of Peking" (Beijing). Center Director Dr. George Pararas-Carayannis was reported as saying that "if the quake hit in a populated area reports of considerable damage could be expected."[57]

News reports the next day located the quake "about 100 miles southeast of Peking and 63 miles northeast of Tientsen" (Tianjin); i.e., "almost precisely in Tangshan".[58] The Chinese Communist party's Central Committee also broadcast a statement that the quake "caused great losses to people's life and property". One of the first reports from Tangshan said "nearly every building in the city ... was flattened."[59] There were several reports of 50 people killed in Beijing, a hundred miles from the epicenter.

According to author Stephen Spignesi, a "couple of days" after the quake Dr. Pararas-Carayannis gave United Press International (UPI) an estimate of 700,000 to 750,000 deaths, based on a similar sized earthquake in Shaanxi province in 1556 that caused 830,000 deaths.[60] Pararas-Carayannis' current web page[61] says only that "it was fairly accurately estimated that there were at least 655,000 people dead," without mentioning by whom or on what basis this estimate was made.

In August the Nationalist Chinese government in Taiwan announced that, according to their agents in China, the death toll was over 100,000, with about 900,000 injured. They also reported that "almost all buildings in Tangshan were leveled", and 80 percent of homes and buildings in Tianjin "suffered damage to some extent".[62]

The following January (1977) the Nationalists released a document they said had been presented at an emergency conference on relief work the previous August by the Hopeh Provincial Committee of the party and the Hopeh Revolutionary Committee.[63] According to this document: "in such seriously stricken areas as Tangshan municipality, and Fengnan and Feng-yun, there were 655,237 persons dead. Some 79,000 persons were seriously injured, and some 700,000 persons suffered various degrees of injuries." Though these figures have been widely cited, it does not appear there has ever been inquiry into how they were derived, of whether they were an initial estimate (made in the first few days following the quake), or had a more solid basis.

In following June it was reported[64] that the Chinese authorities had briefed seismologist Cinna Lomnitz about Tangshan. It was noted that though no figures were provided, they did not deny any published estimates.

Official figures

Section 4C of the Tangshan Earthquake Memorial Wall

A 1988 book by several members of the Chinese State Seismological Bureau states that 242,419 people died in the quake,[65] which reflects the official figure reported by the state-run Xinhua News Agency.[66] A webpage of the Chinese Earthquake Administration dated 2009[67] also attributes "242,769 deaths and 164,851 serious injuries" to the Tangshan quake based on an early 1982 study.[68]

There are various reports that the "official death toll was later given by the Chinese government as 275,000",[69] without specifying a source.

As of 2017, the Tangshan Earthquake Memorial Wall contained the names of 246,465 victims, who were registered by relatives.[70]

Political aspects

The remarkably low death toll of the Haicheng earthquake the previous year – initially said to be fewer than 300,[71] much later estimated at a still very modest 2,041[72] – had been credited to measures taken in response to an accurate and timely prediction. This was touted as demonstrating the validity of the Chinese methods of earthquake prediction (including inspiration from "Mao Zedong Thought"[73]) and "the superiority of our country's socialist system!"[74]

With China in the midst of the Cultural Revolution,[75] "belief in earthquake prediction was made an element of ideological orthodoxy that distinguished the true party liners from right wing deviationists", and it was everyone's duty to criticize those who doubted the feasibility of earthquake prediction.[76] However, the complete lack of warning[77] and hundred-fold greater death toll at Tangshan stood in stark contrast to Haicheng; it was a palpable failure of earthquake prediction that undermined the claims of superiority made for Chinese methods and the socialist system.[78]

As a backdrop to this, and of deep concern to the Chinese Communist Party,[79] was a collectively recognized but unvoiced awareness[80] that in traditional Chinese belief, natural disasters are considered disruptions in the natural order of "heaven" (Tian) and may signify the loss of legitimacy (the "mandate of heaven") of the current government.[81] This view was underlined by a magnitude 6.7 earthquake in southwestern China just three weeks later.[82] On the other hand, an ongoing mass education campaign before the quake showed that the government was aware and concerned, and the prompt and massive response following the quake demonstrated the government's competence to alleviate suffering and restore normal production, drawing on resources from across the nation.[83] This was contrasted with the hardships faced by disaster victims (especially the poor) under previous regimes, where assistance was lacking.[84]

Geology

Tectonic elements surrounding the North China Craton on which Tangshan lies.

Tangshan lies at the northern edge of the Beijing-Tianjin-Tangshan Plain, an alluvial plain that stretches from Beijing to the Sea of Bohai.[85] This plain – the northeastern corner of the great North China Plain – is where sediments eroded from the Yanshan mountains to the north have filled in the ancient Sea of Bohai, with Tangshan near where the shore was about 4,000 years ago.[86] To the south these sediments have formed a layer of weak soils as much as three kilometers thick. At Tangshan and northward these sediments are thinner where the underlying strata crops out to form isolated hills.[87] This underlying strata is a thick (typically 10 km) layer of mainly sedimentary strata such as limestone and sandstone, with large deposits of coal.[88] Tangshan is located particularly over a northeast oriented syncline, a fold in the sedimentary strata that has brought massive deposits of coal close enough to the surface to be mined. In this area the overlying alluvium varies in thickness from several meters to around 600 m (2,000 ft).[89]

Underlying all this is the ancient bedrock of different kinds of metamorphic rock (such as schist, gneiss, quartz, granulite, etc.) that form the Eastern Block of the North China Craton.[90] This craton was formed approximately two billion years ago[91] by the collision of two major crustal blocks that left a belt of uplifted mountains – the Central (China) Orogenic Belt (COB) – that crosses China approximately southwest to northeast, passing just west and north of Beijing.[92] Just north of Zunhua another orogenic belt, the east-west trending Yanshan mountain fault-fold belt (also known as the Yanshan seismic belt) marks the northern edge of the North China Craton (and of the alluvial plain). It is also the location of over half of the destructive earthquakes in Hebei province,[93] as under the plain several fault zones (oriented parallel to the Central Orogenic Belt) terminate against the Yanshan mountains.

Many of these faults are ancient, but have been reactivated by the force transmitted from the collision of the Indian Plate against the Eurasian Plate,[94] making the Eastern Block unusually active seismically, accounting for six of the ten deadliest earthquakes in recorded history.[95]

The Tangshan fault that ruptured 28 July runs right under the center of Tangshan City.[96] One of three faults in the Changdong fault zone, it runs approximately east-northeast (ENE) about 36 km to where it terminates against the north-south trending fault where, just to the south, the secondary M 7.1 quake occurred ("B" on the map).[97] The southern end of the Tangshan fault (it bends slightly at Tangshan) is near Ninghe, which was also the site of a M 6.2 earthquake several hours after the main shock, and an M 6.9 quake ("C") the following November. The Tangshan fault is considered shallow, but corresponds with a deeper and younger fault with somewhat differing characteristics.[98]

Question of prediction

Whether the Tangshan earthquake was predicted has had considerable political as well as seismological significance.

The 1975 Haicheng earthquake (about 400 km [250 miles] northeast of Tangshan) was widely hailed as the first (and, by mainstream seismologists, the only) successful prediction of a major earthquake, demonstrating both that earthquakes could be predicted, and that the Chinese were successfully doing so.[99] The surprisingly light death toll – initial reports were of "very few people killed",[100] but later determined to be a modest 2,041[101]—for this magnitude Ms 7.5[102] quake, attributed to the precautionary measures taken following a definite short-term prediction, was proclaimed as a demonstration of the superiority of China's socialist system,[103] and incidentally a validation of the Chinese methodologies. However, it was later determined that the most important factor in anticipating the Haicheng earthquake was the extended series of significant foreshocks ("powerful messages from nature"[104]), and the low casualty rate was due largely to the time of day, hitting in the early evening when most people were neither at work nor asleep.[105]

Tangshan was not so fortunate.[106] Seventeen months later the 242,419 fatalities of the similarly-sized Tangshan earthquake was therefore a considerable shock politically as well as seismically. While some of this greater mortality might be attributed to the exposure of a larger population, or the time of day (Haicheng was struck in the early evening, Tangshan while most people were asleep[107]), the principal factor appeared to be the failure to take any precautionary measures: Tangshan was entirely unprepared.[108]

At the time, the Chinese methods of earthquake prediction mainly consisted of watching for various precursors, including foreshocks,[109] and were celebrated for their success at Haicheng and elsewhere.[110] Many seismologists consider the Tangshan earthquakes to have not been predicted,[111] even "famously unpredicted",[112] and that it was not predictable due to a lack of precursory anomalous phenomena.[113] Furthermore, an investigation 30 years later found that there was no official short-term prediction of an imminent earthquake at Haicheng, and that, though there were many unofficial predictions of an imminent quake, none of those had a scientific basis.[114] The warnings that were made and precautions taken happened largely at the local level, based on general middle-term predictions, enhanced public awareness due to an educational campaign,[115] and a series of foreshocks. It is significant that at Tangshan there were no perceptible foreshocks.[116]

On the other hand, it is reported[117] that several people at the State Seismological Bureau (SSB) wanted to warn of an impending earthquake somewhere in the region between Beijing and the Bohai Sea, and that this was discussed at several meetings. One of these was a week-long national conference on earthquake predictions and preparation that convened in Tangshan on 14 July (two weeks before the earthquake) where Wang Chengmin is said to have warned there could be a magnitude 5+ earthquake in the Tangshan—Luanxian area between 22 July and 5 August.[118] However, in addition to the distractions of the Cultural Revolution, there was a possible disagreement within the SSB on whether the next large earthquake would be in eastern China (i.e., Beijing area) or western China,[119] and that in May it had been concluded that no major earthquakes would occur in the Beijing–Tangshan area.[120] As it turned out, western China was hit by the magnitude 7.2 Songpan-Pingwu earthquake only three weeks after Tangshan,[121] showing that those arguing for the imminence of an earthquake in Western China were not entirely wrong.

At another meeting, on 26 July, there was a purported suggestion to not issue any warning, to avoid alarming the population.[122] The next morning, at an emergency meeting he requested with the Bureau's leadership, Wang was reportedly told by Deputy Chief Cha Zhiyuan that "We are currently very busy. We will discuss it again next week."[123] However, Cha has disputed this, claiming that Wang said there would be no major earthquakes.[124] Another account says Wang was directed to submit more information, then send a small group to observe the earthquake.[125]

The dilemma: an "abundance of caution" leads to many false alarms.

Some of the bureaucratic reticence to issue warnings and order precautionary measures likely resulted from too many predictions. These were often based on doubtful theories notorious for false alarms[126] that earthquakes can be predicted on the basis of droughts,[127] daily temperatures,[128] variations in geomagnetism,[129] or isolated anomalous phenomena. They were often too broad (magnitude "of at least 4.0 in the area of Beijing, Tianjin, Huailai, Tangshan, Bohai, and Zhangjiakou",[130] "in a few years"[131]) to warrant large-scale societal and economic disruption. Such disruptions could be serious: a false alarm in October, 1976, issued by the Shaanxi provincial government, is estimated to have disrupted the lives of 65% of the population of that province for half a year.[132] It has also been estimated that "in the fall of 1976 about 400 million of the then total population of 930 million of China spent some nights in temporary earthquake shelters."[133] This illustrates the classic dilemma of earthquake prediction: increasing the sensitivity to the possibility of an earthquake (i.e., reducing the failure to predict) increases the number false alarms, which often has a significant cost.[134]

Further information: Earthquake prediction

Comparison

Comparison of the Tangshan death toll – officially 242,419[135]—with other earthquake disasters is problematical because of uncertainty in the statistics. For example, the 1556 Shaanxi earthquake (estimated magnitude of ~8) is generally said to have been the deadliest earthquake disaster in history, with 830,000 deaths, based on Chinese historical records.[136] However, a Chinese language source[137] argues for only 530,000 deaths from the earthquake itself, with the larger number being the total reduction of population due to deaths from all causes (including exposure, disease, and famine) as well as people leaving the region due to economic collapse. Another Chinese source[138] states (without citing any sources) that the 1556 earthquake killed only about 100,000 directly, with another 700,000 dying of disease. Depending on what basis is used, the Tangshan disaster can thus be considered as approximately one-third, one-half, or twice as deadly as the Shaanxi disaster.

The other five deadliest earthquake disasters known in history,[139] with magnitudes ranging from 7.0 to 9.1, have had death tolls just under that of Tangshan's:

Other notably deadly earthquakes in the past century include:

Although unprepared,[140] compared to other earthquake disasters Tangshan did not experience significant common secondary disasters arising from fire, tsunami, landsliding, or flooding due to blocking of rivers or breaching of dikes. A dam holding back a large reservoir just above Tangshan was seriously damaged but did not fail;[141] similarly for another dam that imperiled Tianjin and some outlying districts of Beijing.[142]

The immediate and massive response by the government resulted in the rescue of thousands of people in the first two days (after which mortality increases rapidly),[143] while prompt attention to the problems of clean water, food, and public health avoided the mortality due to epidemic disease and starvation that often follows such disasters.[144]

Cultural references

Chinese director Feng Xiaogang's 2010 drama film Aftershock gives an account of the earthquake and its effects.

See also

Notes

  1. ^ ISC-EHB Event 711732 [IRIS]..
  2. ^ ISC-EHB Event 711773 [IRIS]..
  3. ^ ISC-EHB Event 711732 [IRIS]..
  4. ^ ISC-EHB Event 711773 [IRIS]..
  5. ^ Xinhua News Agency, 29 July 2017; Chen et al. 1988
  6. ^ So-called by numerous sources, of which the voluminous work edited by Housner & He (2002) is the most notable.
  7. ^ Housner & He 2002, Prologue.
  8. ^ See the #Death toll section for the various fatality figures.
  9. ^ Yeoh 2010, p. 273; Press et al. 1975, p. 879. Yeoh called the Tangshan earthquake "[p]robably one of the deadliest wraths of nature in modern times".
  10. ^ Cha 1976, p. 7.
  11. ^ Raleigh et al. 1977, p. 259.
  12. ^ Jennings 1980, p. 69.
  13. ^ ISC-EHB Event 711732 [IRIS]..
  14. ^ Zhu 2002, p. 6.
  15. ^ Butler, Stewart & Kanamori 1979, p. 207. See figure 12 (p. 218) for an illustration. See also Zhu 2002, p. 8, Guo 2002, pp. 33–34.
  16. ^ Jennings 1980, p. 89.
  17. ^ Lomnitz & Lomnitz 1978, p. 109; Jennings 1980, p. 88.
  18. ^ Jennings 1980, p. 89, and see figure 4.17.
  19. ^ Jennings 1980, pp. 88, 92.
  20. ^ Lomnitz & Lomnitz 1978, p. 109.
  21. ^ Zhu 2002, p. 8, and see Table 4, p. 12.
  22. ^ Jennings 1980, p. 88, and see figure 15 in Guo 2002, p. 45.
  23. ^ Jennings 1980, p. 75.
  24. ^ Butler, Stewart & Kanamori 1979, pp. 217–218. See also Jennings 1980, figure 4.23, which plots damage as a function of epicentral distance and a measure of building strength.
  25. ^ Jennings 1980, p. 19.
  26. ^ Jennings 1980, p. 75.
  27. ^ Jennings 1980, p. 69.
  28. ^ Jennings 1980, p. 69; Yang 2002b, p. 176 [6].
  29. ^ Yao 2002, p. 244 [74].
  30. ^ Stoltman, Lidstone & Dechano 2004.
  31. ^ Yang 2002b, p. 172, and see figure 2, p. 182. An isoseismal map can be found in the front matter of Volume 4.
  32. ^ Yang 2002b, p. 172.
  33. ^ Mao, Liang & Cui 2002, p. 231
  34. ^ Jennings 1980, p. 10.
  35. ^ Yang 2002b, p. 180, Table 1.
  36. ^ Yang 2002b, p. 172.
  37. ^ Xu 2002, p. 242.
  38. ^ Zhao 2002, p. 626.
  39. ^ Housner & He 2002, pp. 26–27; Wang, Cui & Liu 2002, p. 749.
  40. ^ Zhao 2002, p. 627.
  41. ^ Mi 2002, p. 765.
  42. ^ Mi 2002, p. 765.
  43. ^ Liao & Gu 2002, p. 1, and see figures 1 and 4, pp. 40 and 41.
  44. ^ Liao & Gu 2002, p. 1.
  45. ^ Liao & Gu 2002, figure 4.
  46. ^ Liao & Gu 2002, p. 2.
  47. ^ Liao & Gu 2002, figure 1.
  48. ^ Liao & Gu 2002, p. 1.
  49. ^ Liao & Gu (2002, pp. 20+) has pictures.
  50. ^ Liao & Gu 2002, pp. 1, 2, 15–16, 18.
  51. ^ Liao & Gu 2002, pp. 8–10.
  52. ^ Liao & Gu 2002, pp. 1. Strengthening is primarily a matter of "joining beam ends" securely so they do not pull apart, crush together, or slip off of a support.
  53. ^ Liao & Gu, pp. 1–2, 8.
  54. ^ Wang, Cui & Liu 2002, p. 750.
  55. ^ Liao & Gu 2002, pp. 1.
  56. ^ From United Press International (UPI), and carried by many newspapers.
  57. ^ UPI: as carried by The Daily Texan, 28 July 1976, page 3.
  58. ^ UPI: in The Daily Freeman (Kingston), 29 July 1976, p. 32.
  59. ^ UPI: in The Berkshire Eagle, 30 July 1976, p. 1.
  60. ^ Spignesi (2005, pp. 47–48) quotes from a geocities.com webpage of "Dr. George" that is no longer available. Spignesi quotes Pararas-Carayannis as saying that, in the 1556 earthquake, "in some counties the average death toll was 60 percent of the total population", and that it was reasonable to expect a similar proportion of deaths at Tangshan since the magnitudes were similar (assuming that the intensity of ground-shaking was also similar), and "since construction standards for this rural area had not changed significantly" (Spignesi 2005, pp. 47–48). However, that premise is false: the large death toll in Shaanxi has been attributed to the yaodong style of construction peculiar to that region, where rooms, and entire buildings, are carved out of a thick layer of soft sediments (loess) that blankets the region, leaving walls of weak material similar to adobe to support the roof (Golany 1992, pp. 7, 1).
  61. ^ "The China Earthquake of 1976", retrieved 18 July 2018.
  62. ^ UPI: Pacific Stars and Stripes, 7 August 1976, p. 11.
  63. ^ UPI: reported in The Redlands (California) Daily Facts, 5 January 1977, p. 5.
  64. ^ Malcolm 1977, p. 1.
  65. ^ Chen et al. 1988.
  66. ^ Xinhua News Agency, 29 July 2017.
  67. ^ CEA 2009.
  68. ^ Lin 1982
  69. ^ E.g.: Housner & He 2002, p. 17, footnote.
  70. ^ Xinhua News Agency, 29 July 2017.
  71. ^ Whitham et al. 1976, p. 268.
  72. ^ Wang et al. 2006, p. 779.
  73. ^ Raleigh et al. (1977, p. 260), quoting the Peking Review (1975, p. 20), state:

    The link between politics and earthquake prediction is well expressed by the following statement: 'This is eloquent proof that in socialist New China, under the leadership of Chairman Mao and the Communist Party and by relying on the masses and professional seismological workers armed with Marxism - Leninism - Mao Tze-tung thought and preserving in practice and summing up experience conscientiously, not only can signs indicating an earthquake be observed but predictions and forecasts can be made and damage can be greatly minimized by doing a good job of precautionary work'.

    See also Cha (1976, p. 7), attributing achievement of rapid progress to "the victory of our great proletarian cultural revolution.

  74. ^ From a Xinhua News Agency press release published in all major Chinese newspapers 13 March 1975, quoted in Wang et al. 2006, p. 781. See also Chu 1976, p. 11, quoted in Geller 1997, p. 434.
  75. ^ Wang et al. 2006, Appendix E has a concise description of the Cultural Revolution.
  76. ^ Raleigh et al. 1977, p. 266; Cha 1976, p. 7.
  77. ^ Malcom 1977.
  78. ^ Cha 1976, p. 7.
  79. ^ Xia 2013, p. 80.
  80. ^ Li 2011, p. 240.
  81. ^ Yeoh 2010, p. 273; Xiao 2013, p. 208.
  82. ^ ANSS: Sichuan 1976 .. See 1976 Songpan–Pingwu earthquake.
  83. ^ Raleigh et al. 1977, pp. 258–259.
  84. ^ Raleigh et al. 1977, pp. 259–260.
  85. ^ Jennings 1980, p. 77.
  86. ^ Jennings 1980, pp. 84–85, and see figure 4.14.
  87. ^ Jennings 1980, p. 84; Xing & Zou 2002, p. 88.
  88. ^ Guo 2002, p. 27.
  89. ^ Zhao 2002, p. 626.
  90. ^ Guo 2002, p. 27.
  91. ^ Some say 1.8 Ga, others 2.5. See Kusky & Li 2003 and Kusky, Windley & Zhai 2007, p. 20 for details.
  92. ^ Kusky, Windley & Zhai 2007, p. 3.
  93. ^ Yang 2002a, p. 50.
  94. ^ Yang 2002a, p. 50.
  95. ^ Kusky, Windley & Zhai 2007, p. 20.
  96. ^ Jennings 1980, p. 89.
  97. ^ See figure 16 in Zhu 2002, p. 23, and figure 13 in Guo 2002, p. 43. The secondary quake occurred on a north oriented section of a fault in a zone that, coming from the southeast, turns north, and then gets complicated.
  98. ^ Guo 2002, pp. 30–31.
  99. ^ Geller 1997, p. 434; Wang et al. 2006, p. 757.
  100. ^ Hammond 1976.
  101. ^ Wang et al. 2006, p. 779.
  102. ^ ISC-EHB Event 711732 [IRIS]..
  103. ^ Wang et al. 2006, p. 781.
  104. ^ Wang et al. 2006, p. 777.
  105. ^ Wang et al. 2006, p. 780.
  106. ^ Kerr 1979, p. 543.
  107. ^ Wang et al. 2006, p. 780.
  108. ^ Xie & Qu 2018, p. 5.
  109. ^ Lomnitz & Lomnitz 1978, pp. 109–110.
  110. ^ Lomnitz & Lomnitz (1978, p. 109) mention "the Lungling and Yenyuen earthquakes, both accurately predicted". See also Jennings 1980 (p. 6) and Chen & Wang 2010 regarding the Sungpan—Pingwu (or Songpan) earthquake.
  111. ^ Jennings 1980, p. 6; Geller 1997, p. 434; ICEF 2011, p. 351.
  112. ^ Scholz 1997.
  113. ^ Lomnitz & Lomnitz 1978, p. 109.
  114. ^ Wang et al. 2006, p. 785.
  115. ^ See also Jennings 1980, pp. 64–67.
  116. ^ Jennings 1980, p. 81.
  117. ^ Bo 2010, Chapter 7.
  118. ^ Bo 2010, p. 281.
  119. ^ Bo 2010, p. 281.
  120. ^ Bo 2010, p. 284.
  121. ^ Chen & Wang 2010, p. 2844.
  122. ^ Bo 2010, p. 282.
  123. ^ Bo 2010, p. 283.
  124. ^ Bo 2010, p. 284.
  125. ^ Peng 2008, p. 9
  126. ^ Chen & Wang 2010, p. 2847.
  127. ^ Bo 2010, p. 279.
  128. ^ Bo 2010, p. 286.
  129. ^ Bo 2010, p. 281.
  130. ^ Bo 2010, p. 281.
  131. ^ Bo 2010, p. 287.
  132. ^ Chen & Wang 2010, p. 2846.
  133. ^ Chen & Wang 2010, p. 2846, citing a Chinese source.
  134. ^ ICEF 2011, p. 351.
  135. ^ Xinhua News Agency, 29 July 2017. The initial estimates of 600,000 to 750,000 deaths were based on a faulty comparison with the Shaanxi earthquake. Spignesi 2005, pp. 47–48.
  136. ^ Hou et al. 1998, p. 549.
  137. ^ Wang 2007.
  138. ^ Wang, Cui & Liu 2002, p. 757.
  139. ^ See U.S. Geological Survey, Significant Earthquakes.
  140. ^ Xie & Qu 2018, p. 5.
  141. ^ Dong & Wang 2002.
  142. ^ Qian & Zhu 2002.
  143. ^ Wang, Cui & Liu 2002, p. 748.
  144. ^ Shen 2002; Wang, Cui & Liu 2002.

Sources

  • ANSS, "Sichuan 1976", Comprehensive Catalog, U.S. Geological Survey .
  • Bo, Zhiyue (2010), "Chapter 7, Sichuan Earthquake", China's Elite Politics: Governance and Democratization, Series on Contempoary China, vol. 19, ISBN 978-981-283-672-4.
  • Cha, Chi-Yuan (August 1976), "General Conditions of Earthquake Studies and Actions in China" (PDF), in Muller, Paul M. (ed.), Proceedings of Lectures by the Seismological Delegation of the PRC, Special Report 43-32, Jet Propulsion Laboratory, pp. 5–11. English translation by JPL of a lecture originally published in 1976 in a special issue of the Journal of the Seismological Society of Japan (in Japanese).
  • Chen, Yong; Tsoi, Kam-Ling; Chen, Feibi; Gao, Zhenhuan; Zou, Qijia; Chen, Zhangli, eds. (1988), The Great Tangshan Earthquake of 1976: An Anatomy of Disaster, Oxford: Pergamon Press, p. 153, ISBN 978-0080348759, LCCN 88005916.
  • Chu, Fung-Ming (August 1976), "Outline of Prediction and Forecast of Haicheng Earthquake of M=7.3" (PDF), in Muller, Paul M. (ed.), Proceedings of Lectures by the Seismological Delegation of the PRC, Special Report 43-32, Jet Propulsion Laboratory, pp. 11–19. English translation by JPL of a lecture originally published in 1976 in a special issue of the Journal of the Seismological Society of Japan (in Japanese).
  • International Commission on Earthquake Forecasting for Civil Protection (30 May 2011), "Operational Earthquake Forecasting: State of Knowledge and Guidelines for Utilization", Annals of Geophysics, 54 (4): 315–391, doi:10.4401/ag-5350.
  • 林[Lin], 泉 [Quan] (1982), 地球的震撼 [The Earth's Shock] (in Chinese), Beijing, China: 中国地震出版社 [Seismological Press].
  • Malcolm, Andrew H. (2 June 1977), "Chinese Disclose That 1976 Quake Was Deadliest in Four Centuries", New York Times, p. 1.
  • Mao, Yingsheng; Liang, ZhiJiang; Cui, Fuwen (2002), "Lightly Damaged Bridges in the High Intensity Earthquake Zone", in Housner, George W.; He, Duxin (eds.), The Great Tangshan Earthquake of 1976, vol. Volume 3, Pasadena, California: Earthquake Engineering Research Laboratory, California Institute of Technology, pp. 231–242 {{citation}}: |volume= has extra text (help).
  • Stoltman, Joseph P.; Lidstone, John; Dechano, M. Lisa. (2004), International Perspectives on Natural Disasters, Springer Publishing, ISBN 978-1-4020-2850-2.

Further reading

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