New Delhi: Micro The tremors are helping to reduce tectonic stress and save India from a catastrophic event, experts said, adding that the country has seen a paradigm shift towards effective response and mitigation. He said that India is fully prepared to deal with the effects of a large-scale earthquake as it has a dedicated, well-equipped and trained force in the form of the National Disaster Response Force (NDRF). He said that the impact of even a large-scale earthquake can be reduced if people and institutions strictly follow bye-laws and codes for building resilient structures.
OP Mishra, director of the ministry, said, “The triple junction in the western part of India near the border with Pakistan continues to stress due to the occurrence of micro-level earthquakes. There are also some earthquakes of magnitude 4 and 5 here.” Earth Sciences’ National Center for Seismology.
A triple junction is a point where three tectonic plates meet and interact. These are important areas of geological activity and can be sites of significant seismic and volcanic activity.
The movement of the plates can lead to a significant build-up of stresses and strains in the Earth’s crust that are eventually released in the form of earthquakes.
Mishra explained, “Triple junctions are rigid and compact and withstand a lot of stress. If it breaks, the whole stress is released, causing a lot of damage.”
Turkey earthquake triggered by rupture of triple junctions
The rupture of this junction, he said, triggered a massive earthquake that ravaged Turkey and Syria, killing thousands.
“Since there were no small earthquakes in the region, a lot of stress accumulated there. Turkey saw several strong earthquakes within 24 hours, because the couple’s area was large and it took time to break down,” Mishra said.
A couple zone is a region where two tectonic plates slide past each other horizontally.
The scientist said, “India is located in a seismically active region, but we are fortunate that we have a lot of micro-earthquakes every day. So the stored-up energy is being released.”
He said that the impact of large-scale earthquakes can be reduced if people and institutions strictly follow bye-laws and codes for building resilient structures.
According to experts, the resonant frequency of a building can play an important role in determining the level of damage it will suffer during an earthquake.
Buildings have natural frequencies of vibration, also called resonant frequencies, which are determined by their mass, stiffness, and shape. Ground motion during an earthquake can excite these natural frequencies, causing the building to vibrate at its resonant frequency.
If the frequency of ground motion matches or exceeds a building’s resonant frequency, the structure will experience significant amplification of ground motion, leading to more intense shaking and potentially significant damage.
“The frequency of buildings in the affected area in Turkiye was less than the frequency of ground motion. Hence, the structures collapsed like a pack of cards,” Mishra said.
59 percent of India’s land is vulnerable to earthquakes
India is divided into four seismic zones based on the probability of seismic activity in each zone.
According to the Ministry of Earth Sciences, 59 percent of India’s land is vulnerable to earthquakes. Zone V is the most seismically active region, while Zone II is the least. About 11 per cent of the country’s area falls in Zone V, 18 per cent in Zone IV and 30 per cent in Zone III and the rest in Zone II.
Zones are used to guide building codes and construction practices.
Mishra said the ministry is further integrating the seismic hazard zone map of the country through seismic microzonation studies. At present, 30 cities with a population of five lakh and above and falling under seismic zones III, IV and V are being covered under the project.
They said the existing zonation map does not consider the physical properties, heterogeneity and behavior of the soil, and compromises on several engineering parameters.
“The parameters will be shared with the Bureau of Indian Standards (BIS) and the urban affairs ministry and municipalities will use them to come up with a new design code,” Mishra said.
Is India ready for earthquakes like Turkey-Syria?
On India’s disaster preparedness and response, experts said the country has a dedicated, well-equipped and trained force – NDRF – which has the means to be at the right place at the right time.
“NDRF and the National Institute of Disaster Management (NIDM) are also undertaking capacity development of the entire country under the overall guidance of the National Disaster Management Authority (NDMA) and reaching out to the community level with the help of all stakeholders, including public enterprises, private organizations and NGOs. including government organizations,” said Major General Manoj Kumar Bindal, former executive director of the National Institute of Disaster Management, Ministry of Home Affairs.
Each state has its own disaster management authority and disaster response force.
There is a total paradigm shift towards effective response and mitigation. Now, India is increasing the resilience of communities to enable people to recover after a disaster. He said that the country is fully prepared to deal with such emergencies.
“Though new buildings are being approved based on designs that comply with seismic codes, the issue we are facing is that more than 90 per cent of the existing buildings are based on outdated technology and most of them are non- There are engineered structures, especially in rural areas,” said Maj Gen Bindal.
It is a herculean task to convert old, non-engineered structures that do not comply with seismic codes, like in Delhi, into earthquake-resistant buildings, he added.
The NDMA has now issued guidelines to train masons and retrofit existing buildings, starting with critical infrastructure related to government and private institutions such as schools and colleges.
A strict monitoring mechanism is required for new buildings and a large-scale exercise is required to map each and every existing building. The expert said that the government may consider relocating some structures which are extremely dangerous.
He said it is not possible to conduct structural stability test of each building as there are few structural engineers.
Major General Bindal said, “The problematic areas are those where plans do not exist, but the building looks good. Such structures need a structural audit and it is a long process.”
Asked what might happen if a large-scale earthquake event, such as the one in Turkey, strikes the Himalayas, he said the earthquake’s destructive potential depends on several factors, including depth and proximity to populated areas. is included.
“It is not necessary that an earthquake of magnitude 7 and above will cause massive damage in the Himalayas. However, if we take the worst case, an earthquake of this magnitude will cause massive landslides, damage to roads, villages , flash floods etc. The impact on urban areas will depend on the epicenter of the earthquake. It depends on which direction the waves move,” said Maj Gen Bindal.
“Therefore, a lot of simulations are being done and models are being made and land use plans are being made. The problem comes when one does not follow the plans,” he added.