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The U.S. Geological Survey has estimated a 99% chance of a magnitude 6.7 earthquake in California in the next 30 years from 2008. In this paper, Fourier transform, mode analysis and commensurability analysis are used to study the earthquake cycle in California and predict the future strong earthquake. The analysis shows that the strong earthquake in California is most likely to occur in 2019, and the prediction was sent to the relevant institutions of United States in 2018. In July 2019 a n M7.1 earthquake occurred in California, which proved our prediction to be correct.

California is the state with the most severe earthquake disaster in the United States. Therefore, earthquake prediction in this area is particularly important. The U.S. Geological Survey (USGS) has made two famous earthquake predictions in California. One is for the Parkfield area in southern California. They found that the earthquake in this area has a cycle of about 22 years. The last earthquake occurred in 1966, so they predicted the next earthquake may occur around 1988 (1983-1993) with probability of 95% [

The historical seismic data of the California area was downloaded from the website of the US Geological Survey (https://earthquake.usgs.gov/earthquakes/search/). A total of 14 strong earthquakes of M6.7 or above occurred from 1900 to 2018 (see

Fourier transform can get the main period of a time series [_{S} ≥ 5.0 earthquakes which occurred in the border area of Shanxi, Hebei and Mongolia from 1494 to 2009 [

Taking the five recent earthquakes in California in 1989, 1992, 1994, 1999 and

No. | Year | Month | date | Lat | Lon | M |
---|---|---|---|---|---|---|

1 | 1906 | 4 | 18 | 37.7 | −122.5 | 7.9 |

2 | 1915 | 11 | 21 | 32 | −115 | 7 |

3 | 1918 | 4 | 21 | 33.7 | −117 | 6.8 |

4 | 1925 | 6 | 29 | 34.3 | −119.8 | 6.8 |

5 | 1927 | 11 | 4 | 34.8 | −120.7 | 6.9 |

6 | 1940 | 5 | 19 | 32.8 | −115.4 | 6.9 |

7 | 1952 | 7 | 21 | 34.9 | −118.9 | 7.5 |

8 | 1956 | 2 | 9 | 31.8 | −116.2 | 6.8 |

9 | 1983 | 5 | 2 | 36.2 | −120.3 | 6.7 |

10 | 1989 | 10 | 18 | 37 | −121.8 | 6.9 |

11 | 1992 | 6 | 28 | 34.2 | −116.4 | 7.3 |

12 | 1994 | 1 | 17 | 34.2 | −118.5 | 6.7 |

13 | 1999 | 10 | 16 | 34.6 | −116.3 | 7.1 |

14 | 2010 | 4 | 4 | 32.2 | −115.3 | 7.2 |

2010 as the starting point, the calculations are based on 5-year and 9-year cycles respectively. The results are as follows:

1) Calculation based on 5-year cycle

1989 1994 1999 2004 2009 2014 2019 2024

1992 1997 2002 2007 2012 2017 2022 2027

1994 1999 2004 2009 2014 2019 2024

1999 2004 2009 2014 2019 2024

2010 2015 2020 2025 2030

2) Calculation based on 9-year cycle

1989 1998 2007 2016 2025 2034

1992 2001 2010 2019 2028 2037

1994 2003 2012 2021 2030

1999 2008 2017 2026

2010 2019 2028 2029

The statistics result shows that 2019 is the most frequent year which appears 5 times, while for other years (2015-2035) they appear only 1-3 times (

The mode is the value that appears most frequently in a data sequence, and reflects the value that has an obvious central tendency point on the statistical distribution of the data. In this paper, we subtracted the data of the earthquake sequence in California to obtain the data sequence of the interval between earthquakes. The frequency statistical analysis was performed, and the earthquake period was extracted. The result is shown in

1) 9 years cycle

1989 1998 2007 2016 2025 2034

1992 2001 2010 2019 2028 2037

1994 2003 2012 2021 2030

1999 2008 2017 2026

2010 2019 2028 2029

2) 12 years cycle

1989 2001 2013 2025

1992 2004 2016 2028

1994 2006 2018 2030

1999 2011 2023

2010 2022

3) 16 years cycle

1989 2005 2021

1992 2008 2024

1994 2020

1999 2015

2010 2026

4) 27 years cycle

1989 2016

1992 2019

1994 2021

1999 2026

2010 2037

According to statistical analysis, after M7 earthquake in southern California in 2010, the most frequent years are 2016, 2019, 2021, 2026 and 2028. Because there is no strong earthquake in 2016, so 2019 is the next most likely years (

The commensurability of the earthquake sequence is an expansion of the earthquake periodicity, namely the mixed law that appears after periods of different lengths are superimposed on each other, which reflects the objective periodic order of strong earthquakes in the region, and it is valuable for earthquake prediction [_{s} ≥ 6.7 earthquake in the Sichuan-Yunnan area was 2008, and the result was an M8.0 earthquake occurred in Wenchuan County, Sichuan Province on May 12, 2008 [

next possible M_{s} ≥ 7.2 earthquake in the Sichuan-Yunnan seismic zone would be 2010. As a result, a M7.1 earthquake occurred in Yushu, Qinghai on April 14, 2010 [_{a} + X_{b} = X_{c} + X_{d}, where X_{a}, X_{b}, X_{c}, and X_{d} are the earthquake occurrence years. The results show that 2019 is the year with the highest probability of earthquakes from 2015 to 2022 (see

We plot the month of 14 California earthquakes on the wind rose map. The most frequent are 5 times for April and October, 4 times for May and November, and 2 times for January and July which show obvious clustering. The above earthquake months are opposite each other, separated by half year, and appear as a straight line on the earth’s orbit, which conforms to the 180-day periodic law we discovered [

Earthquake migration is a phenomenon that earthquake shows a directional migration within an earthquake zone. Studies have shown that the earthquake has an orderly migration phenomenon on the Qilianshan fault zone, Xianshuihe fault zone and north-south seismic zone in many country [

−115˚ to −117˚, from −115.4˚ to −118.9˚, from −116.2˚ west to −120.3˚, and from −116.4˚ to −118.5˚, and all the 4 earthquakes moved from east to west. The longitude of the strong earthquake in 2010 is −115.3˚. According to the above rules, it is speculated that the next strong earthquake will also move westward, possibly between −120˚ and −117˚. The actual longitude of the strong earthquake in July 2019 is −117.6˚, which is consistent with the estimation.

In 2018 we used Fourier transform, mode analysis, and commensurability analysis and predicted that California is most likely to have a strong earthquake of M6.7 or above in 2019, and the prediction was sent to the White House government, California Office of Disaster Mitigation, U.S. Geological Survey and other related agencies in 2018 and received their receptions. An M7.1 earthquake occurred in California on July 6, 2019. The facts have proved our prediction.

The method of USGS scientists can only give the probability of earthquake occurrence in the next 30 years. Our method can predict the earthquake occurrence period within 1 year, which shortens the time window greatly and is of great significance to disaster reduction and prevention in California. Through the month prediction analysis and the epicenter migration analysis, it is found that the law of California earthquakes is clear, and it is possible to use this law to predict the location and month of future strong earthquakes, which provides the possibility for disaster reduction and prevention.

The authors declare no conflicts of interest regarding the publication of this paper.

Guo, G.M. and Jiang, Y.T. (2021) Predicting the 2019 M7 Strong Earthquake in California. International Journal of Geosciences, 12, 941-948. https://doi.org/10.4236/ijg.2021.1210048