The devastating earthquake that recently struck Venezuela has renewed focus on earthquake preparedness across several seismically active regions, including Gujarat, which witnessed one of India’s deadliest earthquakes in Bhuj in 2001. A new scientific study has now offered a more detailed assessment of the state’s seismic hazards, confirming that while Kutch remains the most earthquake-prone region, major urban centres such as Ahmedabad and Rajkot also face significant risks due to different geological factors. The findings have prompted experts to call for stricter implementation of earthquake-resistant building codes, regular seismic audits, and improved disaster preparedness.
The study, titled “Comprehensive Surface Level Seismic Hazard Assessment for the State of Gujarat, India: Implications for Resilient Infrastructure and Communities,” has been published in the Geosciences Journal by Springer. It was conducted by researchers Madan Mohan Rout, Vijay Singh Chufal, Sambit Prasanjit Naik, Sumer Chopra, B. Sairam, and Uday Bhan, representing the Institute of Seismological Research (ISR), Gandhinagar, the University of Petroleum and Energy Studies, Dehradun, and the University of Technology and Management.
Seven Seismic Zones Identified
Unlike earlier seismic assessments that broadly classified large portions of Gujarat under a single seismic category, the researchers divided the state into seven distinct seismogenic zones based on geological characteristics and earthquake history.
The seven zones are:
Kutch Rift Zone
Saurashtra Zone
Cambay Rift Zone
Narmada Rift Zone
South Gujarat Zone
Indus Delta Zone
Aravalli Zone
According to the study, the Kutch Rift Zone remains the most active source of earthquakes in Gujarat. Moderate seismic activity has also been observed in the Cambay and Narmada Rift systems, while the Saurashtra region continues to experience recurring earthquake swarms and moderate tremors.
Study Analysed 350 Years of Earthquake Data
The researchers based their findings on a Probabilistic Seismic Hazard Assessment (PSHA), analysing records of 1,288 earthquakes that occurred over the past 350 years.
Rather than relying solely on traditional seismic zoning maps, the PSHA estimates the probability of future ground shaking by calculating Peak Ground Acceleration (PGA)—a standard measure of how violently the ground is expected to move during an earthquake.
The study assessed the likelihood of experiencing specific levels of ground shaking with 2% and 10% probabilities over a given period.
Kutch Faces the Highest Ground Shaking
The findings show that Kutch remains Gujarat’s most earthquake-prone region. If a major earthquake originates in Kutch, the projected PGA at bedrock is around 0.51 g, while it could reach up to 0.57 g at the surface in some parts of the district.
For comparison, the 2001 Bhuj earthquake recorded PGA values between 0.3 g and 0.6 g, levels that caused widespread destruction across the district. Experts noted that ground acceleration above 0.1 g can significantly affect buildings and infrastructure, highlighting why Kutch continues to require the highest level of preparedness.
The study also found that Bhuj is primarily affected by moderate-to-large earthquakes ranging between magnitude 6.0 and 6.5 occurring at intermediate distances.
Ahmedabad and Rajkot Face Different Types of Risk
Although Ahmedabad and Rajkot are located outside the highest-risk Kutch region, researchers stressed that both cities remain vulnerable—but for different reasons.
According to the study, Rajkot’s seismic hazard is mainly driven by large, distant earthquakes originating from regional Kutch-Saurashtra tectonic sources.
In contrast, Ahmedabad is more vulnerable to nearby moderate earthquakes linked to local faults and the Cambay Rift system. The city is also more susceptible because of its soft sedimentary deposits, which can amplify ground shaking during an earthquake.
The projected PGA for Ahmedabad is between 0.05 g and 0.08 g, with nearby Gandhinagar showing similar values. However, researchers cautioned that lower PGA values do not necessarily mean lower risk, as local soil conditions can significantly increase earthquake impacts.
Existing Seismic Maps May Not Be Enough
The study argues that the broad seismic zoning maps currently used in building design do not fully capture local variations in earthquake hazards.
While national building codes classify large geographical areas under common seismic zones, the new assessment demonstrates that earthquake risk can vary considerably even within the same administrative region.
Researchers believe these findings should prompt a fresh review of building codes, industrial clusters, urban planning, and disaster management strategies across Gujarat.
Lessons from the Venezuela Earthquake
The researchers said the recent Venezuela earthquake underlines the importance of preparedness rather than waiting for disasters to strike.
Professor Sumer Chopra, former Director of the Institute of Seismological Research and currently a faculty member at IIT Roorkee, said critical structures in Ahmedabad should strictly follow building codes designed for seismic hazards.
He stressed the need to review building codes based on updated seismic assessments, conduct regular seismic audits, and organise periodic evacuation training to improve disaster readiness.
Ahmedabad Has Strengthened Building Norms
Officials from the Ahmedabad Municipal Corporation (AMC) said significant improvements have been made since the devastating 2001 earthquake.
According to a senior AMC official, every new building constructed after 2001 must be designed by an authorised structural engineer to meet earthquake-resistant standards.
The official also emphasised that older buildings require regular structural assessments, maintenance, and repairs, particularly before the monsoon season, to ensure they remain safe.
A Roadmap for Safer Infrastructure
The researchers believe the updated seismic hazard assessment offers a more accurate understanding of Gujarat’s earthquake risk than conventional zoning maps. They say the findings will help authorities design safer buildings, strengthen critical infrastructure, improve emergency planning, and make communities more resilient against future earthquakes.
With Gujarat having experienced two earthquakes exceeding magnitude 7.7 in less than two centuries—both centred in Kutch—the study serves as a timely reminder that earthquake preparedness must remain a long-term priority across the state, not just in its highest-risk districts.
Also Read: 7.2 And 7.5 Magnitude Back-To-Back Earthquakes Hit Venezuela; Tsunami Alerts Issued https://www.vibesofindia.com/7-2-and-7-5-magnitude-back-to-back-earthquakes-hit-venezuela-tsunami-alerts-issued/
