Recent natural disasters such as the California fires and Hurricane Michael suggest that we’re living in an increasingly precarious world. However, are earthquakes also increasing in frequency?
Spoiler alert – it’s a MYTH! The overall average of earthquakes remains unchanged, but earthquake frequency does vary from year to year, depending on the energy cycles of fault lines, as described in our previous post.
Earthquakes in the News
Information is now available instantly via social media, online, and TV news. While instant access to information is great, it can also lead to cognitive biases. Clustering illusion is one example. This comes into play when we see multiple devastating earthquakes in the news.
For example, three significant earthquakes occurred in a six-month span of 2015: Nepal, M7.8 (April); Chile, M8.3 (September); Afghanistan, M7.5 (October). Our brains start to think earthquakes are increasing, and we see patterns that don’t exist.
To overcome these cognitive biases, let’s look into the facts.
Historical Earthquake Frequency
If we chart known earthquakes from 1900 to the present day, it appears that earthquake frequency is increasing dramatically. However, this is misleading: for the first half of the 1900s, we were not recording earthquakes, nor did we have an adequate network of seismic monitoring stations to record earthquakes globally.
The proliferation in stations over the past 60 years has significantly improved our ability to record seismic activity. For example, the Southern California Seismic Network grew from 20 seismic monitoring stations in 1960 to nearly 400 in 2010. The International Seismological Centre shows all the current international registry of stations:
Recent Earthquake Statistics
With the majority of significant fault lines now observed by seismic monitoring stations, we can analyze more precise statistics on the past 18 years of earthquake activity. On average, there are 16 major earthquakes (M 7.0-8.0+) worldwide per year. Additionally, we experience 142 strong earthquakes (M 6.0-7.0) worldwide annually.
In 2018, from January to November, there have been 12 major earthquakes, as indicated by the gray circles in the image below. And in that same time frame, 106 strong earthquakes.
Get a real-time view of earthquake frequency: use USGS’s notification tool to receive automated emails when an earthquake occurs.
