Dozens of earthquakes in Kon Tum due to reservoir-induced seismicity
On July 29, the Earthquake Information and Tsunami Warning Center - Institute of Geophysics, issued a notice of 17 earthquakes occurring in the morning in Kon Plong district (Kon Tum province). Specifically, from 0:00 to 12:00 on July 29, Kon Plong district recorded 17 earthquakes with magnitudes ranging from 2.5 to 3.8. Previously, on July 28, 21 earthquakes with magnitudes ranging from 2.5 to 5.0 also occurred in this area.
In an interview with Lao Dong, Mr. Nguyen Xuan Anh - Director of the Institute of Geophysics (Vietnam Academy of Science and Technology) - said: “Previously, information had been released that earthquakes in this area are reservoir-induced seismicity, not unusual. Many years ago, when the cause of earthquakes was unknown, they were considered unusual, but in recent years, after research and surveys, it has been basically concluded that these are reservoir-induced earthquakes, occurring relatively frequently. In the past two days, many earthquakes have occurred, including a 5.0 magnitude earthquake, the largest in the area to date. Previously, in 2022, there was a 4.7 magnitude earthquake, and this 5.0 magnitude earthquake is the largest to date.
This magnitude earthquake is also classified as medium magnitude. Earthquakes with magnitudes below 5.0 are small, light, and unlikely to cause damage. Earthquakes with magnitudes from 5.0-6.0 are medium-sized and can cause damage; weak, poorly resistant buildings may collapse,” Mr. Nguyen Xuan Anh informed.
Mr. Nguyen Xuan Anh also affirmed that these are predicted reservoir-induced earthquakes. Almost all reservoirs have induced seismicity. For example, in Hoa Binh, Son La, Quang Nam, A Luoi... all have induced seismicity.
“Two years ago, when earthquakes occurred in Kon Tum, the Institute sent a working group to research and survey, and this work is still ongoing. Research cannot be done in a day or two. Initial results have shown that earthquakes in the area have magnitudes not exceeding 5.0. These are preliminary and very important studies.
Research has provided assessments and forecasts that earthquakes in this area are unlikely to exceed a magnitude of 5.5. However, these are only preliminary assessments, and more observational data and evaluations are needed. Induced seismicity still occurs depending on the response of each reservoir, often lasting for a period and can also last for many years. For example, the Song Tranh reservoir has experienced earthquakes for 10 years, and earthquakes still occur now,” Mr. Nguyen Xuan Anh said.
Support needed for residents to reinforce houses and structures
Mr. Nguyen Xuan Anh said: “The Institute of Geophysics has installed 11 monitoring stations in Kon Tum to study and promptly determine the activity level of earthquakes. Earthquakes in Kon Tum will continue and affect densely populated areas and key structures, especially in the epicenter area. Authorities need to regularly update to provide seismic-resistant design plans for key structures and residential areas,” while emphasizing: Localities must inventory damage phenomena, review houses with weak seismic resistance to reinforce and upgrade for safety; educate residents on what to do during an earthquake and how to mitigate it, helping people reinforce their houses well. These are basic solutions. In the long term, there must be planning on where dams and hydropower reservoirs can be built, along with related measures to ensure feasible and appropriate results. Relocating residents is impractical because the current earthquake level in this area is still medium.
“The Institute is still continuing to research and evaluate the earthquake activity level to provide appropriate recommendations. Currently, the necessary measures, as I mentioned above, are to review and inventory weak structures with poor seismic resistance that are easily affected by earthquakes to reinforce them. Educate residents on how to respond during an earthquake. These are immediate solutions. Currently, monitoring agencies are still continuing to research and evaluate to see if there are any abnormalities in the area,” Mr. Nguyen Xuan Anh said.
