Jimin News Reporter Wang Liangliang Hu Xiuwen
Recently, there have been frequent earthquakes in the Pacific Rim. On the 11th, a magnitude 7.6 earthquake occurred in Papua New Guinea , and a magnitude 6.9 earthquake occurred in Taiwan, China on the 18th. On the 19th local time, a magnitude 7.7 earthquake occurred in Mexico . Earthquakes occur frequently, has the seismic belt entered an active period? Mexico History There were three major earthquakes on on September 19. Is it a coincidence? With these questions in mind, Jimu News reporter interviewed Professor Wang Dun from China University of Geosciences (Wuhan) and asked him to answer it for us.
Professor Wang Dun is mainly engaged in the research of observing seismology, artificial intelligence seismology and seismology.
Jimu News Reporter: A magnitude 7.7 earthquake occurred in Mexico on September 19 local time. This day is the anniversary of two major earthquakes in Mexico. On September 19, 1985, a magnitude 8.0 earthquake in Mexico killed thousands of people; on September 19, 2017, a magnitude 7.1 earthquake killed more than 360 people. Three major earthquakes occurred on the same date, and this special day caused concern. Is this a coincidence?
On September 19, in Mexico City, the capital of Mexico, people who were taking refuge outdoors comforted each other (Picture source: Xinhua News Agency)
Wangdun: should be a coincidence. It is a statistical coincidence that three earthquakes occurred on the same date, as well as other statistical coincidence events, such as the relationship between rising oil prices and earthquakes. Statistical seismologist Professor Zhuang Jiancang and others have done relevant research and used relevant data from 2003 to 2015 for analysis. They found that the time of the two occurred is good, that is, the increase in oil prices is significantly correlated with the occurrence of a global earthquake. But this is a statistical pseudo-correlation and there is no clear physical correlation.
Jimu News Reporter: In recent times, earthquakes of magnitude 6 or above have occurred in countries and regions such as Taiwan, Papua New Guinea, Indonesia . Does it mean that the earthquake zone has entered an active period?
Wangdun: The current global seismic activity is still within the normal range. It is normal for an earthquake of about 7 or 8 in the Pacific Rim earthquake zone. The earthquake in Hualien, Taiwan was 6.9 and Taitung was 6.5, not considered a major earthquake. We generally believe that earthquakes above magnitude 7 are major earthquakes, while earthquakes above magnitude 8 and 9 are huge earthquakes. The magnitude 7.7 earthquake in Mexico was a major earthquake.
As for whether it has entered the active period, we can compare the 2004 Indian Ocean earthquake. On December 26, 2004, a magnitude 9.3 earthquake occurred in the Indian Ocean, with the epicenter located in the west of Sumatra Island. The earthquake and its tsunami affected the surrounding countries such as Bangladesh, India, Malaysia , Myanmar , Singapore and Thailand, causing serious damage. The aftershock magnitude also reached 7 or 8. Since the 9.3-magnitude Indonesia earthquake, earthquake activity in Indonesia has been significantly active.
Generally speaking, an earthquake of magnitude 8 or 9 will occur, and a series of strong aftershocks will occur. Only such events will cause the crustal movement in the area to enter an active period.
Taiwan earthquake caused the Gaoliao Bridge to be broken (Picture source: China Times News Network)
After the earthquake, we are concerned about whether this earthquake is the precursor of the latter strong earthquake or the main earthquake, and the seismic activity in the area will slowly subside. Like Taiwan earthquake , we generally believe that main earthquake has occurred, and the intensity of seismic activity is slowly weakening. At present, there is no characteristic of a larger earthquake happening later.
Jimu News Reporter: Global Warming Are climate changes such as glacier melting related to earthquakes?
Wangdun: Climate change is somewhat related to regional earthquakes. For example, there is a slight ice shock on the Antarctic ice sheet . As the temperature rises, glaciers melt accelerate, and ice shock activity has increased. Ice shock is a vibration caused by ice rupture and melting, which is different from an earthquake. Climate change is long-term, and no research has pointed out its association with large earthquakes and destructive earthquakes.
(Source: Jimu News)
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