Have Magnitude 7.0+ Earthquakes Increased?

Major earthquakes receive a lot of media attention these days. Major earthquakes do not need to occur near land to earn a breaking news banner on major news websites. The widespread prevalence of major earthquake reports in the media leads to the question: “Are major earthquakes becoming more common these days?” I will address this question by examining trends in magnitude 7.0 and greater earthquake activity since 1900 in this article.

Why Care about Major Earthquakes?

Why should we care about major earthquake activity? Luke 21:11 suggests that we will hear about great earthquakes-rather than regular earthquakes-in diverse places prior to the Second Coming of Christ.

“And great earthquakes shall be in divers places, and famines, and pestilences; and fearful sights and great signs shall there be from heaven.” (Luke 21:11)

I already published a study about magnitude 8.0 and greater earthquake activity so why focus on magnitude 7.0 and greater earthquake activity? Some people may argue that focusing solely on magnitude 8.0 and greater earthquakes causes us to ignore many major earthquakes that have transpired over the past several decades. The earthquake in 2008 earthquake in Sichuan (7.9) and the 2010 earthquake in Haiti (7.0) are two of the many major earthquakes not accounted for in a study featuring only magnitude 8.0 and greater earthquakes.

I again utilized two data sources to account for the magnitude 7.0 and greater earthquakes that have taken place since 1900.

• The U.S. Geological Survey’s Centennial Earthquake Catalog dataset. I rely on this dataset to account for magnitude 7.0 and greater earthquakes that have taken place from 1900-2007.[1]
• The U.S. Geological Survey’s Preliminary Determination of Epicenters (PDE) dataset. I rely on this dataset to account for magnitude 7.0 and greater earthquakes that have taken place since 2008.[2]

The following graph illustrates magnitude 7.0 and greater earthquake activity each year since 1900.

Magnitude 7.0+ By Year

The above graph somewhat resembles a pulse monitor graph with periods of relatively high activity and periods of relatively low activity. 2010 was one of the more active years in recent decades in terms of magnitude 7.0 and greater earthquake activity.

Magnitude 7.0+ By Decade

I created a second chart comparing magnitude 7.0 and greater earthquake activity across different decades to see how last decade’s activity compares to other decades in the past.

Surprisingly, the last decade experienced a relatively low amount of magnitude 7.0 and greater earthquake activity.

The graph and chart presented in this article suggests we may not be living in an extraordinary period of major earthquake activity while my magnitude 8.0 and greater earthquake chart suggests that we’ve seen a historically high number of major earthquake activity recently. Thus, how a person depicts recent great earthquake activity depends on whether they use “magnitude 7.0 and greater” or “magnitude 8.0 and greater” to define what a “great earthquake” is.

• One could argue that “magnitude 8.0 and greater” better defines what a “great earthquake” is than “magnitude 7.0 and greater” since magnitude 8.0 and greater earthquakes are much rarer (and thus much more distinguished) than magnitude 7.0 and greater earthquakes.

I hope you found this article on trends in magnitude 7.0 and greater earthquake activity since 1900 informative. If you have any questions or comments please share in the comments section below. If you would like to read about trends in magnitude 6.5 and greater earthquakes, click this link for my article on the topic: Has Magnitude 6.5 Earthquake Activity Increased?

Note

1. Centennial Earthquake Catalog numbers from 1900 to 2007 were obtained from a text file found on the USGS’s Centennial Earthquake Catalog page: http://earthquake.usgs.gov/data/centennial/centennial_Y2K.CAT ↩
2. PDE numbers for 2008 to the present were obtained on May 18, 2018 from the USGS’s Search Earthquake Archives, which can be accessed at the following link: http://earthquake.usgs.gov/earthquakes/search/ I set the custom magnitude at 7.0 and set the search range starting on January 1, 2008. Under advanced options I selected: “US – National Earthquake Information Center, PDE”. Under output options, I choose CSV and ordered results by time: oldest first. ↩