IIT Kanpur Study Warns: Kanpur and Prayagraj Face Deep Liquefaction Risk from Himalayan Earthquakes
Even though the plains cities of Kanpur and Prayagraj lie hundreds of kilometres away from the Himalayan seismic belt, they could face unusually severe ground instability if a major earthquake strikes the region.
A 17-year-long research project led by the Indian Institute of Technology Kanpur has revealed that both cities are highly vulnerable to deep soil liquefaction — a phenomenon that could amplify destruction far beyond what is typically expected.
The findings were shared by Prof. Nihar Ranjan Patra of the Civil Engineering Department after extensive experimental and numerical investigations involving soil sampling, laboratory testing, and seismic modelling.
What the Study Found
According to the research, liquefaction in Kanpur and Prayagraj could extend up to 30–40 metres below the surface during a major earthquake.
Under normal circumstances, liquefaction effects are usually confined to depths of 8–10 metres.
Liquefaction occurs when water-saturated, loose sandy soils temporarily lose their strength due to intense shaking, behaving more like a liquid than a solid.
When this happens, buildings can tilt, sink, or collapse even if they were structurally sound before the tremors.
To reach these conclusions, Prof. Patra’s team collected soil samples from 43 locations across Kanpur and Prayagraj, using boreholes and assistance from the Public Works Department.
While soil samples from most states were extracted from depths of up to 30 metres, in Kanpur and Prayagraj, boreholes were drilled as deep as 80 metres to examine subsurface behaviour in detail.
The research project, funded by CSIR, the Department of Science and Technology (DST), and BRNS, began in 2008 and covered multiple states,s including Gujarat, Haryana, Uttar Pradesh, and Bihar.
However, the findings in Kanpur and Prayagraj — and in parts of Varanasi — were particularly concerning.
Why Cities Far from the Himalayas Are at Risk
At first glance, it may seem counterintuitive that cities far from the Himalayan epicentre zones could face such intense impact.
However, the explanation lies in geology rather than geography.
Alluvial Soil of the Indo-Gangetic Plain
Kanpur and Prayagraj are located in the Indo-Gangetic alluvial plain, formed by centuries of river deposition. These soils are typically:
- Loose
- Sandy
- Highly porous
- Water-saturated
The study found that the upper 8–10 metres of soil in many areas of these cities consist of loose, saturated sandy layers — precisely the type most vulnerable to liquefaction during seismic shaking.
Deep Soft Sedimentary Layers
Unlike rocky terrains that absorb and dampen seismic energy, the soft sedimentary layers extending 30–40 metres below the surface in these cities can transmit and even amplify seismic waves.
Instead of dissipating energy, these shallow layers act as conduits, allowing seismic waves from distant Himalayan quakes to travel upward with significant force.
This increases surface shaking intensity despite the epicentre being far away.
Wave Amplification Effect
Soft soils tend to resonate with certain frequencies of seismic waves.
This phenomenon, known as site amplification, can make shaking stronger and longer-lasting than in nearby regions with firmer ground.
In practical terms, even a distant Himalayan earthquake could produce disproportionately high ground motion in these plains cities.
Earthquake Risk Mapping Prepared
Based on the extensive field and laboratory data, Prof. Patra’s team has developed an earthquake risk map for Kanpur and Prayagraj.
He emphasised that such risk maps must be integrated into urban planning and construction practices.
In many developed countries, seismic microzonation maps are mandatory references before construction approvals are granted.
Builders and urban planners assess soil behaviour, liquefaction risk, and amplification potential before designing foundations.
“In these regions, construction should strictly follow earthquake risk mapping guidelines,” Prof. Patra advised. “If such maps are considered during planning and structural design, major hazards can be significantly reduced.”
Implications for Urban Development
Kanpur and Prayagraj are densely populated and rapidly expanding urban centres. High-rise buildings, bridges, flyovers, and underground utilities could face severe damage if deep liquefaction occurs.
The study serves as a warning that seismic safety cannot be judged solely by distance from a fault line.
Subsurface geology plays a decisive role in determining how destructive an earthquake will be at a given location.
As Himalayan seismic activity remains an ongoing concern, integrating scientific risk mapping into policy, infrastructure planning, and building codes may prove crucial in safeguarding millions of residents across the Indo-Gangetic belt.
