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The trend of increasing strong earthquakes worldwide deserves attention – Analysis – Eurasia Review

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By He Jun

There have been severe earthquakes around the world in recent days. On April 3, a magnitude 7.3 earthquake struck the eastern sea region of Hualien County, Taiwan, at a depth of 12 km. As of April 5, this earthquake had claimed 12 lives, injured 1,123, and left 634 people still trapped. On April 5, on the other side of the globe, a magnitude 4.8 earthquake with a depth of about 5 km occurred on the East Coast about 60 km from New York City. Although the magnitude of this earthquake was not significant, it was the strongest earthquake in New York in 140 years, a region where large earthquakes rarely occur. In Japan, a magnitude 6.1 earthquake occurred on April 2 off the east coast of Honshu; On April 6, another magnitude 5.3 earthquake struck well off the east coast of Honshu at a depth of 10 km.

Looking at the longer time frame and broadening the scope, one can see that in the last year or two there has been an increasing trend of large-scale earthquakes occurring around the world. On January 1 this year, a large earthquake occurred on the Noto Peninsula in Japan, the strongest magnitude of which reached 7.6. On January 3, a magnitude 5.5 earthquake occurred in Argentina; and on January 4, a magnitude 5.7 earthquake struck the Fiji Islands.

According to the China Earthquake Networks Center (CENC), there were a total of 129 earthquakes of magnitude 6 or greater worldwide in 2023, including 19 earthquakes of magnitude 7 or greater, with the largest two having magnitude 7.8 earthquakes in Turkey on February 6th. If we consider earthquakes of magnitude 7 or greater, this is essentially the same as the average annual frequency of 18 times since 1900, significantly higher than the activity level of 7 earthquakes of magnitude 7 or greater in 2022. Global seismic activity of earthquakes with a magnitude of 7 or greater shows a clear trend of transition from weak to strong. According to incomplete statistics, there were at least 12 earthquakes of magnitude 6 or greater worldwide in December 2023 alone.

Due to the temporal and spatial distribution of earthquakes, the coastal areas of the Pacific Ocean and the Himalayan volcanic seismic zone remain the high-risk areas for global earthquakes. Currently, more than 90% of earthquakes worldwide still occur in this seismic zone. According to statistics from CENC, in 2023, 95% of global earthquakes with a magnitude of 7 or greater occurred in the Eurasia seismic zone and on the northeastern boundary of the Australian plate. Earthquakes with a magnitude of 7 or greater occurred seven times in the Eurasian seismic zone and 11 times on the northeastern edge of the Australian plate. From January to June 2023, there were 14 earthquakes of magnitude 7 or greater worldwide, accounting for 73.7% of the total number of earthquakes for the entire year, showing a relatively concentrated spatial and temporal distribution of earthquake activity.

According to the CENC, there were a total of 18 earthquakes with a magnitude of 5 or more in China in 2023. Among them, there were 11 earthquakes with a magnitude of 5 or more on the mainland, including 2 earthquakes with a magnitude of 6 or more; There were 4 earthquakes of magnitude 5 or greater in offshore areas. Taiwan experienced three earthquakes with a magnitude of 5 or greater, with the strongest occurring on Oct. 24 with a magnitude of 5.9 in the offshore area of ​​Hualien County. Some analysts have noted that earthquakes of magnitude 5 or greater are significantly weaker in Taiwan, and seismic activity remains relatively quiet during earthquakes of magnitude 7. The level of seismic activity in China decreased significantly in 2023 compared to 2022 (26 events). ), which represents the lowest frequency year since 2000. In Taiwan, seismic activity above magnitude 7 remained quiet for 17 years since the magnitude 7.2 earthquake in the offshore Hengchun area on December 26, 2006, the longest quiet period since 1900. However, the magnitude 7.3 earthquake, which occurred in the eastern sea area of ​​Hualien County on April 3, immediately refuted the previously suggested notion of a prolonged period of calm for major earthquakes in Taiwan.

As a geological phenomenon, earthquakes represent a type of geological activity that occurs frequently, and it seems difficult to accurately capture and define the regularity of their occurrence and evolution. A prominent manifestation is the significant controversy over whether earthquakes are “predictable.” Based on the incomplete understanding of ANBOUND researchers, the prevailing opinion in the seismological community in China is that earthquakes cannot be predicted. Therefore, it seems that since the accurate prediction of the Haicheng earthquake in the last century, the Chinese seismological community has been reluctant to make earthquake predictions and reluctant to take responsibility for earthquake predictions and related research.

However, the complexity of accurately predicting earthquakes does not mean that humanity is unable to study their patterns, nor does it mean that it must completely abandon its efforts to predict earthquakes. As the trend of large earthquakes has increased worldwide over the past two years, we may need to remain vigilant and pay attention to the increasing trend of larger earthquakes. Based on statistical data, some seismic experts estimate that the active period of earthquakes typically lasts about 10 to 20 years. Although this does not necessarily mean that this is the period of active earthquakes on a global scale, China's seismically active period is not yet over. Some experts also point out that since the Wenchuan earthquake in 2008, there have been no earthquakes of magnitude 7 or greater in mainland China for nearly 15 years. Through the regular analysis of earthquakes, China is facing a difficult seismic situation, which requires increased attention to the trend of increasing severe earthquakes and strengthening research efforts.

In recent decades, globalization has continued to deepen, with improvements in free trade and supply chains enabling global distribution of investment in manufacturing and services. If there is an increase in severe earthquakes worldwide in the future, it will have certain impacts on the industrial investments and planning decisions of multinational corporations. For example, future large-scale capital and technology-intensive investments may need to take into account the impact of earthquakes and other natural disasters. Similar investment plans could focus more on avoiding areas with high earthquake activity. Although large earthquakes are a very rare natural disaster phenomenon, for certain key industries with massive investments, they still represent an investment planning risk that must be actively avoided as much as possible.

Final conclusion of the analysis:

Statistical data shows that large earthquakes around the world show a clear trend of increasing intensity. Given the trend of more frequent large earthquakes, relevant countries need to pay attention. For certain key industries with massive investments, greater consideration needs to be given to earthquake risk.

He Jun is a researcher at ANBOUND