The temporary increase or decrease in seismic activity is part of the normal fluctuations in the frequency of earthquakes. Both increases and decreases in this frequency worldwide are not strong indicators that a major earthquake is imminent.
Why Are There So Many Earthquakes?
Data from the Advanced National Seismic System (ANSS) in the United States shows that the number of recorded earthquakes has increased in recent years, not because there are more earthquakes occurring, but because there are more seismic measuring tools available that can record more events.
The United States Geological Survey (USGS) currently locates about 20,000 earthquakes globally each year, or approximately 55 per day. Thanks to advancements in communication and an increasing public interest in natural disasters, people are now more aware of earthquakes than ever before.
Earthquake in Turkey, February 6, 2023. (Photo: ANews).
How Many Earthquakes of Magnitude 7 or Greater Occur Each Year?
According to long-term records (dating back to around 1900), the USGS estimates that there are approximately 16 significant earthquakes each year. This includes 15 earthquakes with magnitudes in the range of 7 and one earthquake with a magnitude of 8.0 or greater. Over the past 40-50 years, the USGS has recorded more than 10 times the average number of significant earthquakes in a single year.
The year with the highest total of recorded significant earthquakes was 2010, with 23 earthquakes of magnitude 7.0 or higher. There have been several years when the total number of significant earthquakes was much lower than the average of 16. For instance, in 1989, only 6 significant earthquakes occurred, and in 1988, there were just 7.
At What Magnitude Does Damage Begin to Occur in an Earthquake?
This issue is not easy to determine. There is no specific magnitude at which damage will occur. It depends on various factors such as the distance from the earthquake, the type of ground you are on, and the construction of buildings. Damage is generally not expected until the magnitude of the earthquake is around 4 or 5.
Can a “Super Earthquake” of Magnitude 10 or Greater Occur?
No, earthquakes with a magnitude of 10 or higher cannot occur. The magnitude of an earthquake is related to the length of the fault line along which it occurs. This means that the longer the fault line, the larger the earthquake. A fault line is a fracture in the rock layers that make up the Earth’s crust; along the fault line, rocks on either side move past each other. No sufficiently long fault line has been recorded to create an earthquake of magnitude 10, and if such a fault did exist, it would stretch around nearly the entire Earth.
The largest earthquake ever recorded had a magnitude of 9.5 on May 22, 1960, in Chile along a fault line nearly 1,000 miles long… making it a true “super earthquake.”
