Degraded apartment buildings on Tho Quan street, Hanoi, face risk of collapse if an earthquake happens. (Photo: vietnamplus.vn)Hanoi has nearly 1,600 old apartment buildings, many of which have fallen intodisrepair.
According to Construction Work Management Department under the Ministry ofConstruction if an earthquake measuring 4-5 on the Richter scale occurs, oldapartment building could face extensive damage.
Newly-built blocks can resist quakes measuring eight on the Richter scale.
Associate Professor Cao Dinh Trieu, vice president of Vietnam Association ofGeophysicists and director of Institute for Applied Geophysics, said Hanoi islocated in the Red River-Chay River fault zone where earthquakes with amagnitude of 5.1-5.5-magnitude have happened.
The recurrence period for an earthquake measuring magnitude 5.3 in Hanoi is1,100 years, and the last strong earthquake occurred more than 700 years ago in1285.
“If an earthquake occurs in the city, it will cause big tremors," he said.
"If an earthquake with a magnitude of four or more happens, old apartmentbuildings will be at serious risk."
Because of poor ground, Hanoi might feel vibrations from other majorearthquakes in other countries. Recently the local residents reported vibrationaffected by earthquakes from neighbouring countries like Laos and China.
At about 8.45pm on December 24, 2021, many people living in high-rise buildingsin Hanoi felt strong shaking which was determined to be the impact of a 5.5magnitude earthquake in Laos.
In recent years, many localities in Vietnam reported a series of stimulatingearthquakes. A strong earthquake with magnitude 6.9 happened in 1935 in DienBien Basin (1935).
Trieu said the impact of aftershocks of large earthquakes occurring in anothercountry also causes potential risks.
He said the Institute of Geophysics had in the past proposed building a systemof nine earthquake monitoring stations in Hanoi. However, after a period ofoperation, the system was suspended due to a shortage of funds for generalmaintenance.
Trieu said big cities or large industrial zones in developed countries likeChina all have monitoring systems which carefully check earthquakes and caneven monitor the level of terrain deformation at large construction areas.
Many other countries have building regulations that take into account possibleearthquakes and insist monitoring stations should be in place.
Vietnam does not have this kind of law now so the installation of earthquakemonitoring stations at construction sites is limited, except for those athydroelectric projects or dams.
He emphasised the need to focus on seismic resistance of construction works,not only in Hanoi but also Vietnam, especially high-rise buildings to ensuresafety and minimise potential risks that may occur.
He added: “I think we need to pay attention to strengthening andre-establishing the network of earthquake monitoring stations in Hanoi.
"This is important because recently every earthquake that has happened hascaused many buildings to shake, possibly because the foundations of buildingsin Hanoi can be a bit weak.”
Nguyen Xuan Anh, president of Institute of Geophysics, said installingearthquake monitoring stations is an important solution to record data as wellas to analyse and evaluate the intensity of earthquakes in order to makespecific recommendations for each area.
Citing specific examples in Kon Tum and Quang Nam provinces with frequentstimulant earthquakes in the past five years, he said in early 2023, hydropowerinvestors coordinated with the Institute of Geophysics to install eightearthquake monitoring stations in these localities.
Those stations have provided quick earthquake reports, collected detailed dataand assessed danger levels. On that basis, the stakeholders are responsible fortraining earthquake response skills to managers and residents in thepossibly-affected area and neighbouring regions, he said./.
VNA
