Vietnam needs to assess earthquake risks and adapt from the "pour foundation and build house" stage.

A 7.7-magnitude earthquake on March 28 with its epicenter in Myanmar shook South Asia, causing severe damage and killing many people.

This can be considered the strongest earthquake that this country has suffered in the past 100 years.

Devastation in Myanmar after the earthquake (Photo: Getty).

Although the epicenter was far away, thousands of kilometers away from Vietnam, the fact that many people in Hanoi and Ho Chi Minh City could clearly feel the tremors is raising many concerns.

Dan Tri reporter interviewed Dr. Nguyen Xuan Anh, Director of the Earthquake and Tsunami Warning Center, Institute of Earth Sciences, Vietnam Academy of Science and Technology to clarify the impact of the earthquake, as well as Vietnam's response capacity to this natural disaster.

Vietnam once had a 6.8 Richter earthquake.

Sir, why when the 7.7 Richter scale earthquake occurred in Myanmar, many people living in Hanoi and Ho Chi Minh City felt the shaking but other areas did not feel anything?

- The feeling of earthquake vibration depends on three main factors.

First is the distance. The epicenter of this earthquake is in Mandalay, Myanmar (22.013 N, 95.922 E). This area is more than 1,000 km away from us. When an earthquake occurs, seismic waves will spread, but the farther away they are, the less they will be.

The second factor is the wave propagation environment, which is the ground. For example, an earthquake in Myanmar will cause seismic waves to propagate from there to Hanoi or Ho Chi Minh City, which will be affected by the ground along the propagation path.

Depending on the characteristics of the ground, the waves can be strengthened or weakened, although basically the farther they travel, the weaker they become. Historically, it has been recorded that places farther from the epicenter are more severely affected than those closer to the epicenter due to the resonance factor of the ground with the seismic waves.

This dependence is quite complex and so it is entirely possible that Hanoi is further from Myanmar than Hoa Binh, but due to this interaction, Hanoi may experience stronger shaking. Studies on the effects of earthquakes from distant sources need to be done to assess this phenomenon. It can be seen that earthquakes in Myanmar have a strong impact in Bangkok, Thailand.

Dr. Nguyen Xuan Anh, Director of the Earthquake Information and Tsunami Warning Center, Institute of Earth Sciences, Vietnam Academy of Science and Technology, shares about the impact of earthquakes (Photo: Thanh Dong).

Third is the building factor. Basically, the taller the building, the easier it is to feel the shaking. In fact, in big cities like Hanoi and Ho Chi Minh City, there are many high-rise buildings, so many people can clearly feel the shaking from this earthquake.

However, according to our assessment, due to the distance of the earthquake, the impact of the earthquake on Vietnam is very little. Therefore, when it occurred, the Earthquake Information and Tsunami Warning Center issued a warning of only "0" risk level.

We still need studies to assess the ground effects from distant earthquakes like the recent one.

People in high-rise buildings in Ho Chi Minh City evacuated outside when they felt tremors (Photo: Contributor).

We expect aftershocks in the coming period. However, they will be weaker than the main shock and the possibility of affecting Vietnam is very low.

For example, on March 28, there were actually earthquakes in Myanmar, but in Vietnam, we only felt the tremors from the biggest earthquake, which occurred at 1:20 p.m.

In the past, when talking about earthquakes, many people considered it a foreign affair. Why has Vietnam been continuously affected by earthquakes in recent years? In addition to aftershocks from earthquakes abroad, have there also been many earthquakes recorded in the Northwest or Kontum?

- This needs to be viewed from two factors.

The first is the impact of climate change. Humans have created many unusual changes that have significantly increased the intensity and frequency of natural disasters such as super typhoons and earthquakes.

Natural hazards can be linked together, for example heavy, intense rainfall can change the ground and have a long-term impact on earthquake activity. The construction of hydropower projects has caused induced earthquakes in some areas such as the Northwest, Quang Nam and Kontum.

Vietnam has also recorded many earthquakes (Photo: Thanh Dong).

Regarding the second aspect, in the past, in urban areas like Hanoi or Ho Chi Minh City, there were not many high-rise buildings, so people could hardly feel the earthquake as clearly as they do now. When more people feel it and the information is shared, we will feel like the impact of the earthquake is more.

In fact, earthquakes have always occurred in Vietnam. Even in the Northwest region, strong earthquakes with magnitudes of up to 6.7-6.8 have been recorded.

In addition, unlike hurricanes, earthquakes are natural disasters with very long return periods, especially the larger the earthquake, the longer it will return. This period can be 100 years, several hundred years, or even thousands of years, for example, the 2023 M = 7.8 earthquake in Türkiye has a return period of several hundred years.

According to Dr. Xuan Anh, earthquakes are a type of natural disaster with a very long recurrence cycle, especially the larger the earthquake, the longer it takes to repeat (Photo: Thanh Dong).

Therefore, in-depth studies are needed to assess whether the number of earthquakes in Vietnam is currently greater than before, as it is a combination of many factors.

What are the high-risk areas for earthquakes in Vietnam, sir?

- Vietnam has an earthquake zoning map and an earthquake hazard assessment. Based on this zoning, Hanoi is in the zone with earthquakes of level 7 and level 8. Meanwhile, the Northwest region is where the strongest earthquakes can occur in our country.

This place has recorded earthquakes of magnitude 6.7-6.8 in 1935 and 1983.

In the Central Highlands, there have been many small earthquakes recently caused by stimulation from lakes and hydroelectric dams.

Controlling the seismic resistance of structures is particularly important.

What is our country's current capacity to monitor and warn of earthquakes and tsunamis?

- Vietnam has more than 30 national seismic stations to monitor earthquake activity across the country. In addition, there are nearly 100 local seismic stations monitoring key projects such as hydropower plants and areas planned for nuclear power development.

Data from the stations will be immediately transmitted to the Earthquake and Tsunami Warning Center located in Hanoi for automatic analysis, thereby determining the epicenter and focal depth of the earthquake to issue the fastest warning.

The Earthquake Information and Tsunami Warning Center in Hanoi receives information from seismic stations (Photo: Thanh Dong).

According to regulations, we will issue notices for all earthquakes with a magnitude of 3.5 or higher. However, we are now also announcing earthquakes with a magnitude of 2.5 to provide additional information to the public.

Note that, not only our country but also in the world, no country can predict the exact time of an earthquake. Even countries with many earthquakes like Japan or the most advanced countries. Basically, predicting the magnitude in an area can be done, but predicting the exact time of an earthquake is not possible.

Need to install vibration meter in high-rise building

The fact that an apartment building in Ho Chi Minh City showed signs of wall cracks after the aftershocks of the recent earthquake in Myanmar has made many people wonder about the earthquake resistance of buildings in Vietnam. What is your opinion on this issue?

- Earthquake prevention is very important for construction projects.

Currently, in Vietnam, there are standards for earthquake-resistant design of buildings, in which earthquake hazard maps with ground acceleration values ​​for the whole country have been developed. Accordingly, all buildings must be designed to withstand earthquakes according to this standard.

According to Dr. Xuan Anh, ensuring the earthquake resistance of structures is very important (Photo: Tran Khang).

The role of local authorities and relevant specialized agencies is very important. It is necessary to not be subjective, to conduct periodic inspections, monitoring and evaluations of the seismic resistance quality of the construction according to the Government's earthquake prevention regulations.

For example, in Hanoi, there are many apartment buildings and collective houses that are degraded and have weak structures that need earthquake risk assessment.

When a structure is weak and cannot withstand earthquakes, it is very dangerous. Authorities need to periodically evaluate it to have a plan to either reinforce it or demolish it to ensure the safety of the people.

For high-rise buildings, we also recommend many times that vibration meters should be installed to assess how the vibration is and how much impact it has.

Currently, the assessment of the impact on construction is mainly done by people using their senses. These monitoring devices allow to accurately determine the level of vibration, and from that data, give appropriate warnings and recommendations to people.

In the near future, we will build key projects such as high-speed railways, subways, nuclear power plants or marine economic development projects that must also carefully calculate the risk factors of earthquakes and tsunamis.

Urgent need to build a national program to assess earthquake hazards

From a professional perspective, in your opinion, what are the solutions that need to be implemented soon to improve earthquake response capacity in Vietnam, especially in the context of climate change and increasingly complex natural disasters?

- We emphasize the urgency of developing a national program to assess earthquake hazards across the country.

The earthquake zoning and earthquake hazard assessment map we are using has been around since 2006. Although it has been updated since then, it requires updating data and making detailed assessments, especially of dangerous areas.

Dr. Xuan Anh emphasized the urgency of building a national program to assess earthquake hazards nationwide (Photo: Thanh Dong).

Through risk assessment, it will provide scientific and technical basis for socio-economic development orientation; help policy makers to make the most effective regulations and legal documents.

For example, we should not build cities with many high-rise buildings in places with high earthquake risks because it will be costly; in large urban areas such as Hanoi and Ho Chi Minh City, there needs to be detailed zoning of earthquake risks to plan for sustainable city development.

Second, we need to improve our earthquake and tsunami warning capabilities. Typically, we need to increase the number of monitoring stations, and as I shared earlier, we need to have equipment to directly measure vibrations in high-rise buildings.

Third, we need to step up the dissemination of earthquake response skills to the public. In fact, the recent earthquake has also exposed the lack of earthquake response skills among many people.

How are countries in the region adapting to earthquakes?

- Countries located on the belt of large earthquakes such as Japan, Indonesia and the Philippines have proactively built long-term earthquake adaptation strategies.

In Japan, the government strictly regulates building standards, requiring buildings to have a very high level of earthquake resistance. They also invest in early warning systems, regular drills, and strong communications to raise public awareness.

However, building structures with high resilience means large investment costs.

Therefore, here I re-emphasize the importance of earthquake hazard assessment and risk assessment research.

How to determine the appropriate earthquake level for each area to come up with appropriate and effective economic and technical solutions. The implementation of this project will provide scientific arguments, help save unnecessary costs and serve sustainable socio-economic development.

Thank you for the chat!

Photo: Thanh Dong

Source: https://dantri.com.vn/khoa-hoc/viet-nam-can-danh-gia-rui-ro-dong-dat-thich-ung-tu-khau-do-mong-xay-nha-20250401071241997.htm