Editing Earthquake prediction (section)

=== 1985–1993: Parkfield, U.S. (Bakun-Lindh) ===
{{anchor|Parkfield}}

The "[[Parkfield earthquake]] prediction experiment" was the most heralded scientific earthquake prediction ever.<ref>{{Harvtxt|Geller|1997|loc=§6}} describes some of the coverage.</ref>{{efn|1=The most ''anticipated'' prediction ever is likely [[#1990: New Madrid, U.S. (Browning)|Iben Browning's 1990 New Madrid prediction]], but it lacked any scientific basis.}} It was based on an observation that the Parkfield segment of the [[San Andreas Fault]]{{efn|1=Near the small town of [[Parkfield, California]], roughly halfway between San Francisco and Los Angeles.}} breaks regularly with a moderate earthquake of about M 6 every several decades: 1857, 1881, 1901, 1922, 1934, and 1966.<ref>{{Harvnb|Bakun|McEvilly|1979}}; {{Harvnb|Bakun|Lindh|1985}}; {{Harvnb|Kerr|1984}}.</ref> More particularly, {{Harvtxt|Bakun|Lindh|1985}} pointed out that, if the 1934 quake is excluded, these occur every 22 years, ±4.3 years. Counting from 1966, they predicted a 95% chance that the next earthquake would hit around 1988, or 1993 at the latest. The [[National Earthquake Prediction Evaluation Council]] (NEPEC) evaluated this, and concurred.<ref>{{Harvnb|Bakun|Breckenridge|Bredehoeft|Burford|1987}}.</ref> The U.S. Geological Survey and the State of California therefore established one of the "most sophisticated and densest nets of monitoring instruments in the world",<ref>{{Harvnb|Kerr 1984, "How to Catch an Earthquake"}}; {{Harvnb|Roeloffs|Langbein|1994}}.</ref> in part to identify any precursors when the quake came. Confidence was high enough that detailed plans were made for alerting emergency authorities if there were signs an earthquake was imminent.<ref>{{Harvnb|Roeloffs|Langbein|1994|p=316}}.</ref> In the words of ''[[The Economist]]'': "never has an ambush been more carefully laid for such an event."<ref>Quoted by {{Harvnb|Geller|1997|p=440}}.</ref>

1993 came, and passed, without fulfillment. Eventually there was an M 6.0 earthquake on the Parkfield segment of the fault, on 28 September 2004, but without forewarning or obvious precursors.<ref>{{Harvnb|Kerr|2004}}; {{Harvnb|Bakun|Aagaard|Dost|Ellsworth|2005}}, {{Harvnb|Harris|Arrowsmith|2006|p=S5}}.</ref> While the ''experiment'' in catching an earthquake is considered by many scientists to have been successful,<ref>{{Harvnb|Hough|2010b|p=52}}.</ref> the ''prediction'' was unsuccessful in that the eventual event was a decade late.{{efn|1=It has also been argued that the actual quake differed from the kind expected,<ref name=":10"/> and that the prediction was no more significant than a simpler null hypothesis.<ref>{{Harvnb|Kagan|1997}}.</ref>}}

{{further|Parkfield earthquake}}