Editing Earthquake prediction (section)

=== 1975: Haicheng, China ===
{{anchor|Haicheng}}

The M 7.3 [[1975 Haicheng earthquake]] is the most widely cited "success" of earthquake prediction.<ref>E.g.: {{Harvnb|Davies|1975}}; {{Harvnb|Whitham|Berry|Heidebrecht|Kanasewich|1976|p=265}}; {{Harvnb|Hammond|1976}}; {{Harvnb|Ward|1978}}; {{Harvnb|Kerr|1979|p=543}}; {{Harvnb|Allen|1982|p=S332}}; {{Harvnb|Rikitake|1982}}; {{Harvnb|Zoback|1983}}; {{Harvnb|Ludwin|2001}}; {{Harvnb|Jackson|2004|pp=335, 344}}; {{Harvnb|ICEF|2011|p=328}}.</ref> The ostensible story is that study of seismic activity in the region led the Chinese authorities to issue a medium-term prediction in June 1974, and the political authorities therefore ordered various measures taken, including enforced evacuation of homes, construction of "simple outdoor structures", and showing of movies out-of-doors. The quake, striking at 19:36, was powerful enough to destroy or badly damage about half of the homes. However, the "effective preventative measures taken" were said to have kept the death toll under 300 in an area with population of about 1.6 million, where otherwise tens of thousands of fatalities might have been expected.<ref>{{Harvtxt|Whitham|Berry|Heidebrecht|Kanasewich|1976|p=266}} provide a brief report. {{Harvtxt|Raleigh|Bennett|Craig|Hanks|1977}} has a fuller account. {{Harvtxt|Wang|Chen|Sun|Wang|2006|p=779}}, after careful examination of the records, set the death toll at 2,041.</ref>

However, although a major earthquake occurred, there has been some skepticism about the narrative of measures taken on the basis of a timely prediction. This event occurred during the [[Cultural Revolution]], when "belief in earthquake prediction was made an element of ideological orthodoxy that distinguished the true party liners from right wing deviationists".<ref>{{Harvnb|Raleigh|Bennett|Craig|Hanks|1977|p=266}}, quoted in {{Harvtxt|Geller|1997|p=434}}. Geller has a whole section (§4.1) of discussion and many sources. See also {{Harvnb|Kanamori|2003|pp=1210–11}}.</ref> Recordkeeping was disordered, making it difficult to verify details, including whether there was any ordered evacuation. The method used for either the medium-term or short-term predictions (other than "Chairman Mao's revolutionary line"<ref>Quoted in {{Harvtxt|Geller|1997|p=434}}. {{Harvtxt|Lomnitz|1994|loc=Ch. 2}} describes some of circumstances attending to the practice of seismology at that time; {{Harvnb|Turner|1993|pp=456–458}} has additional observations.</ref>) has not been specified.{{efn|1=Measurement of an uplift has been claimed, but that was 185&nbsp;km away, and likely surveyed by inexperienced amateurs.<ref>{{Harvnb|Jackson|2004|p=345}}.</ref>}} The evacuation may have been spontaneous, following the strong (M 4.7) foreshock that occurred the day before.<ref>{{Harvnb|Kanamori|2003|p=1211}}.</ref>{{efn|1=According to {{Harvtxt|Wang|Chen|Sun|Wang|2006|p=762}} foreshocks were widely understood to precede a large earthquake, "which may explain why various [local authorities] made their own evacuation decisions".}}

A 2006 study that had access to an extensive range of records found that the predictions were flawed. "In particular, there was no official short-term prediction, although such a prediction was made by individual scientists."<ref name=":13">{{Harvnb|Wang|Chen|Sun|Wang|2006|p=785}}.</ref> Also: "it was the foreshocks alone that triggered the final decisions of warning and evacuation". They estimated that 2,041 lives were lost. That more did not die was attributed to a number of fortuitous circumstances, including earthquake education in the previous months (prompted by elevated seismic activity), local initiative, timing (occurring when people were neither working nor asleep), and local style of construction. The authors conclude that, while unsatisfactory as a prediction, "it was an attempt to predict a major earthquake that for the first time did not end up with practical failure."<ref name=":13"/>

{{further|1975 Haicheng earthquake}}