An analysis of the hidden vulnerabilities: The role of construction quality in seismic risk mitigation in low-to-moderate seismicity regions

• A M 3.6 earthquake impact is identified using macro-seismic survey • Regions with low to Moderate seismicity areas can have potential for significant damage • The extent of damage from even moderate earthquakes can be amplified by construction practices and soil amplification because of the poor quality of construction. • Increased public awareness and preparedness are crucial for mitigating earthquake risk, even in areas of low seismicity. People living in low seismicity areas may underestimate the potential for larger, infrequent earthquakes, leaving them unprepared for rare but impactful events. Understanding and acknowledging this risk is essential for ensuring safety and readiness in these seemingly stable regions. Tamil Nadu, India's southernmost state, experiences frequent tremors due to its low to moderate seismicity. Vellore District in Northern part of Tamil Nadu which is prone to Moderate Seismic Hazard Zone III. This district has had frequent tremors in the past with the Magnitude of 2 to 4.3. This area is prone to low to moderate seismicity due to its frequent seismic activity in Tamil Nadu. The present paper discussed the M 3.6 earthquake that occurred on 29.11.2021 felt around more than a 50km radius and created damage to the houses in the area. A detailed reconnaissance survey was conducted in the felt area to understand the causes of the tremors and damage phenomenon on the housing of the area using climatological, induced, geological, and ground verification studies. The study revealed that even though the earthquake is only 3.6 Magnitude, the far-away sources can also damage the buildings due to their construction practices and the underlying soil amplification in the area.