6 hours Ago By Siddhardha Gattimi
HYDERABAD: The 5.3-magnitude earthquake that struck the state in December last year has sparked discussions about disaster preparedness in Telangana. However, experts asserted that the earthquakes experienced in the state are of low magnitude and do not pose a significant threat to public safety.
Speaking to TNIE, Dr N Purnachandra Rao, former chief scientist at the National Geophysical Research Institute (NGRI) and former director of the National Centre for Earth Science Studies (NCESS), explained the geological causes of these seismic events. While Telangana and Andhra Pradesh lie on a relatively stable continental region and consist of old and hard rock formations, minor, low-intensity earthquakes are still common.Earthquakes occur primarily because of movements along fault lines — fractures in the Earth’s crust where blocks of rock move relative to each other.
These movements are often found at tectonic plate boundaries, where two or more plates interact. However, in the case of Telangana, the quakes originate from small fractures within the Indian tectonic plate itself.“The boundary forces acting on the Indian tectonic plate transfer stress to these fractures, known as faults.
When these faults are reactivated, small earthquakes occur,” explained Dr Rao. This process is referred to as fault reactivation, wherein pre-existing fractures experience renewed movement due to accumulated stress over time.Geological factors influencing earthquakesDr Rao elaborated on how the faults in Telangana formed.
The Indian tectonic plate is millions of years old and has undergone significant geological stress due to natural processes. The formation of river valleys like the Godavari and Krishna over centuries has also contributed to the development of fractures in the rock formations. These faults become points of weakness where seismic activity can occur.
“Whenever external forces, such as plate boundary interactions or minor adjustments within the plate, act on these faults, they reactivate, resulting in low-magnitude earthquakes in Telangana,” he clarified.Locating earthquake epicentresThe former NGRI scientist explained how earthquake epicentres—the points on the Earth’s surface directly above the source of an earthquake—are identified. Data collection plays a crucial role in seismology, with scientists continuously monitoring seismic activity across the country.
“We conduct airborne and surface geophysical surveys, which involve collecting seismic, gravity and magnetic data, to map the subsurface faults. Additionally, we study fault orientations to understand earthquake behaviour. These are also documented in the ‘Seismotectonic Atlas of India’ for further research and analysis by GSI,” he said.
Impact on Telangana’s infrastructureDespite the occasional tremors, Dr Rao assured that Telangana’s infrastructure remains safe. “Andhra Pradesh and Telangana fall under Seismic Zones 2 and 3, which indicate low to moderate seismic activity. The risk of earthquakes causing structural damage is minimal,” he stated.
While minor earthquakes in Telangana and Andhra Pradesh may raise concerns, scientific analyses indicate that they do not pose a serious threat to public safety. Ongoing research and advanced seismic monitoring help geologists understand these phenomena better, ensuring that preparedness measures remain adequate for the region’s seismic risk level.Seismic activity in the Bay of BengalWhen questioned about the significance of the recent earthquake in the Bay of Bengal, Dr Rao clarified that the region is not a tectonic plate boundary, making large earthquakes relatively rare.
A magnitude 6 earthquake was recorded in May 2014. However, recent observations suggest increasing seismic activity in the Bay of Bengal. Dr Rao linked this to the movement of the Indian and Australian tectonic plates.
“Millions of years ago, India and Australia were part of a single tectonic plate. As the plate began moving northward, India collided with the Eurasian plate, while the Australian plate moved away and subducted (sank) beneath the Indonesian plate. The difference in movement speeds between these plates has created a diffuse plate boundary zone, leading to seismic disturbances in the Bay of Bengal,” he explained.
Furthermore, the Indian and Australian plates are currently sliding over the 90° East Ridge, a massive underwater geological structure. This interaction is forming a new type of plate boundary motion, increasing tectonic stress and leading to earthquakes in the Bay of Bengal region.
