In the last two decades, major earthquakes have occurred in many parts of the world including Indonesia, Japan, China, Italy, Nepal, Afghanistan, Pakistan, Ecuador, Mexico, Morocco, and the Turkey-Syria border. On April 3, Taiwan was struck by an earthquake of 7.4 magnitude. These earthquakes cannot be treated as random occurrences, as earthquake-prone regions share some tectonic similarities.
Earthquakes occur in certain regional bands. The spatial distribution is explained by the theory of plate tectonics, which explains how the Earth’s outermost layer, the lithosphere, is broken into 15 major fragments or plates which are constantly moving relative to each other. This is why powerful earthquakes are concentrated along convergent plate boundaries like the Himalayas, a tectonic product of the convergence of the Indian and Eurasian plates.
The earthquake in Nepal in 2015 caused severe devastation in central Nepal, but spared India. This was an example of an earthquake originating from under the Himalayas. On April 4, 2024, the region around Manali in Himachal Pradesh was struck by an earthquake of magnitude 5.3. On the same day, 119 years ago, an earthquake occurred near Kangra, not far from Manali, killing thousands of people and levelling the buildings in the region.
The story of two earthquakes
In the Taiwan region, the Philippine Sea plate is moving northwest towards the Eurasian plate at a velocity of about 7.8 cm per year, which is faster than the motion of the Indian plate. Lying 160 km off the coast of China, Taiwan was formed at a convergent boundary of the Philippine and Eurasian plates in the western Pacific Ocean. It is a country of strong earthquakes. The latest one occurred near the city of Hualien on the eastern coast. In 1999, the Chi-Chi earthquake of magnitude 7.7 occurred in the central part of Taiwan and impacted the western region. It killed more than 2,430 people and left 11,305 wounded. It caused more than 50,000 buildings to collapse and partially damaged as many.
The Hualien earthquake killed at least 13 people and injured about 1,000. Most of the deaths were caused by earthquake-triggered rockfalls and not by toppled buildings. Despite being of nearly comparable magnitude, the 2024 earthquake has caused minimal damage compared to the 1999 earthquake.
What is remarkable is that even in Hualien city, located within the epicentre of the latest earthquake, where shaking is expected to be most intense, only about 50 residential buildings and a nine-storey building partially collapsed. In the capital city of Taipei, only 10 houses were severely damaged. These were reported to have been constructed before the implementation of stringent building codes following the 1999 Chi-Chi earthquake.
The 1999 earthquake was a major wake-up call that led to critical administrative reforms to improve emergency response and reduce disasters. The government passed the Disaster Prevention and Protection Act and set up two national centres to handle earthquake coordination and training. Between the Chi-Chi and Hualien earthquakes, Taiwan mounted a consistent effort in implementing building codes.
Today, Taiwan’s earthquake preparedness is among the most advanced in the world. The island nation has the most advanced earthquake-monitoring network and early warning systems. Widespread awareness campaigns and drills on earthquake safety have improved the public’s understanding of earthquake risks. The government constantly updates the earthquake safety requirements of the new and existing building stock and incentivises residents by offering subsidies to improve the quake resistance of buildings.
Taiwan has been able to reach sound scientific judgements based on how severe the shaking would be in each location. With the knowledge of the frequency of earthquakes in each source and how severely the ground shakes in a particular area, specific seismic codes can be designed, and specific construction norms can be followed. Taiwan could also use new technologies such as seismic dampers and base isolation systems. Taiwan’s most iconic building, Taipei 101, escaped damage during the latest earthquake. One of the components that helped the building retain its integrity was a tuned mass damper, a 660-metric-ton steel sphere suspended by cables within the tower. This acts as a giant pendulum to counter any motion of the building.
What India can do
As India is going through a major phase of infrastructural expansion in many tectonically unstable regions including the Himalayas, sometimes flagrantly violating the norms that should be followed in ecologically sensitive areas, earthquake safety should be of particular concern. All infrastructural projects must comply with seismic safety regulations. The Taiwan earthquake provides important lessons for India. These include following seismic codes, constructing safer engineered structures, and overcoming inadequacies in the enforcement and non-compliance of seismic codes. These codes, unique to a particular region, are prepared based on local earthquake activity, building types, and construction materials. Indian code IS 1893 specifies seismic designs based on seismic zonation maps so that buildings do not collapse. In some parts of India, traditional architectural styles possessing earthquake resistivity can be rediscovered and encouraged.
C.P. Rajendran is an adjunct professor at the National Institute of Advanced Studies, Bengaluru, and author of the book ‘The Rumbling Earth: The Story of Indian Earthquakes’
