The Central Highlands is currently experiencing a dry season, with water levels in hydroelectric reservoirs low. However, over the past four days, the Kon Plong district in Kon Tum Province has recorded more than 60 earthquakes. Experts are explaining the reasons behind this phenomenon.
Between July 28 and July 31, a total of 63 earthquakes occurred in the Kon Plong district of Kon Tum Province. The strongest quake registered a magnitude of 5.0, causing tremors across a wide area that included the Central Highlands and several provinces in Central Vietnam. Some damages have been reported. Additionally, on the morning of August 1, another earthquake measuring 3.3 in magnitude was recorded in the area.
Earthquakes occurring in the Kon Plong district of Kon Tum are assessed by experts from the Institute of Geophysics as induced seismicity, resulting from the pressure exerted by the water in the hydroelectric reservoir on the underlying fault system, causing earthquakes to occur sooner than natural patterns would suggest.
So, why are earthquakes occurring continuously in a low-water reservoir? Dr. Nguyen Xuan Anh, Director of the Earthquake Notification and Tsunami Warning Center, explained that induced seismicity does not occur immediately after the reservoir is filled but has a delay; it takes time for the water to permeate and exert pressure on the underlying fault system, which can take several months, or even years, to manifest.
The earthquake on July 28 caused some damage in the epicenter area.
Associate Professor Dr. Cao Dinh Trieu, former Deputy Director of the Institute of Geophysics, further noted that the timing of induced earthquakes following reservoir filling depends on various factors such as the size of the reservoir, the volume of stored water, and the process of water accumulation, indicating the need for more specific studies to assess these impacts.
Induced seismicity in the Kon Plong district of Kon Tum has been frequent since April 2021, after the Thượng Kon Tum Hydropower Plant began to fill. Over the past three years, this area has recorded hundreds of earthquakes, a significant increase compared to the number of earthquakes occurring in the previous century.
The majority of earthquakes in Kon Tum are weak and unlikely to cause damage. However, the earthquake at the end of August 2022, which registered 4.7 in magnitude, and the earthquake on July 28, which measured 5.0, could pose a risk of damage in the epicenter area.
Dr. Xuan Anh cautioned that earthquakes can cause ground cracking; induce shaking that may damage structures and lead to liquefaction of the ground, resulting in sinking or tilting of buildings; landslides, and rockfalls from cliffs, potentially lowering groundwater levels and affecting water sources.
He cited the example of the Cao Bang earthquake in 2019, which had a magnitude of 5.4, causing a stream in the Dam Thuy commune to dry up and leading to the depletion of water sources supplying thousands of residents in the area, with some boreholes yielding muddy water. Similarly, the Moc Chau earthquake in 2020, which registered 5.3, caused the Na Muong commune to experience water gushing from the ground.
