However, the study also pointed out that it is necessary to pay attention to geological and tectonic characteristics and civil activities, and to predict early possible disasters to minimize risks.
Stimulated earthquakes appear in parallel with the development of hydroelectric plants.
According to the Institute of Geophysics, from the beginning of 2021 to April 22, 2022, 169 earthquakes occurred in Kon Plong district, Kon Tum province. Particularly, from April 15 to 18, 22 earthquakes with a magnitude of 2.5 - 4.5 on the Richter scale were recorded. Up to now, although the frequency is lower, earthquakes continue to occur.
According to the reports of the People's Committees of the localities, the earthquakes have not caused any loss of life or property but have made people worried and insecure. The subject of "concern" is the Upper Kon Tum Hydropower Plant which had just been put into operation at that time. Based on this exogenous factor and the characteristics of the intensity of the earthquakes, seismologists have initially pointed out that the main cause of the earthquakes is earthquakes stimulated by the process of storing water in hydropower reservoirs.
Experts from the Institute of Geophysics said that induced earthquakes are a phenomenon that occurs when water is pumped into a hydroelectric reservoir, causing changes in pressure and balance of forces underground. This can trigger cracks and displacement of rock blocks, causing tremors. This issue has been mentioned in many reports in Vietnam and around the world, such as: The 6.3 Richter magnitude induced earthquake that occurred in Sichuan, China in 2008 due to the construction of the Zipingpu reservoir, killing 80,000 people; the 5.7 Richter magnitude earthquake that occurred in Oklahoma, USA in 2011 due to oil and gas exploitation; and the 6.3 Richter magnitude earthquake that occurred in Koyna, India in 1967 due to the construction of the Koyna reservoir...
In Vietnam, the induced earthquakes can be mentioned as: The induced earthquake at Hoa Binh Lake, which occurred on May 23, 1989, had a magnitude of 4.9 on the Richter scale and was the first induced earthquake recorded in Vietnam. This earthquake is believed to have been caused by the water storage activities of Hoa Binh Hydroelectric Reservoir; the induced earthquake at Son La Lake in 2010 and continued to be recorded in the past time, a series of induced earthquakes with magnitudes from 2.6 - 5.3 on the Richter scale occurred and may continue...
Regarding the recent earthquakes in Kon Tum, Mr. Ho Tien Chung said that it is necessary to pay attention to volcanic activity in the past 10,000 years. It is not excluded that earthquakes can trigger volcanic reactivation. This is an important task that needs to be researched to prevent and have response plans.
According to researchers from the Institute of Geosciences and Mineral Resources, we are getting used to the appearance of induced earthquakes along with the development of construction and exploitation of hydropower plants nationwide in recent times. Besides the great benefits brought by hydropower, there are still many disadvantages mentioned from social issues to construction. One of them is the problem of induced earthquakes.
Proposal for in-depth study of induced earthquakes
The group of authors from the Institute of Geosciences and Mineral Resources has evaluated existing documents as well as surveyed and re-examined geological, tectonic and geological hazard characteristics in the applied area to provide additional information and propose solutions, and conduct in-depth research on induced earthquakes.
The results show that, in addition to the risks of endogenously induced earthquakes, manifestations of exogenous activities were also recorded in previous investigation reports. From there, the authors propose further research directions to reduce risks in general and to solve the risk of geological disasters caused by earthquakes in Kon Tum and neighboring areas.
According to Mr. Ho Tien Chung - Deputy Head of the Tectonics and Geomorphology Department, Institute of Geosciences and Mineral Resources, it is necessary to continue monitoring to have more detailed assessments on the issue of induced earthquakes. Accordingly, in the coming time, it is necessary to consider additional investigations and research to clarify tectonic activities in the region and the relationship between tectonic activities and geological disasters, flash floods, and civil activities in the region.
Specifically, it is necessary to add earthquake monitoring stations in high-risk areas, densely populated areas, and key national projects; conduct research and assess the impact of earthquakes on landslides and flash floods in the area; conduct research and assess the existence of active faults and the safety level of dams in the area; and study geological disasters related to active volcanoes in the Central and Central Highlands regions of Vietnam.
In addition, besides solid structures built according to technical regulations, the current civil works of the people are "brick and tile" but the structure is often sketchy and does not comply with technical regulations. Therefore, it is necessary to advise on the level of impact of earthquakes and the resistance capacity of civil works in the area, to avoid loss of life and property.
“It is necessary to conduct early research to assess the phenomena of active faults, earthquakes, and volcanoes because sooner or later, when the country develops, we also need to pay attention to building large projects such as nuclear power, new energy, etc. It is very necessary to invest in training staff and preparing technical infrastructure to be able to take the lead,” Mr. Ho Tien Chung emphasized.
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