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The Pakistan Meteorological Department (PMD) has explained the reason behind the frequent mild earthquakes in Karachi within a 24-hour period.
The recent earthquake tremors in Karachi were caused by an active fault line in Landhi, said Amir Haider Leghari, head of the Pakistan Meteorological Department’s Tsunami Warning Center.
He explained that the Landhi fault line is historically known and currently active. This means it releases energy through frequent small earthquakes, with intensity gradually decreasing each time it moves.
Leghari noted that Karachi lies near the junction of three major tectonic plates – Indian, Arabian, and Eurasian. These plates are in a slipping position, which typically causes less dangerous tremors.
However, the Balochistan region lies on a subduction zone where one plate slides beneath another. That zone is more dangerous and capable of generating tsunamis during strong quakes.
According to Leghari, the last major tsunami-causing earthquake near the Makran coast occurred in 1945. He assured that Karachi’s eastern delta region is less prone to destructive quakes.
READ: Mild earthquake hits Karachi
“There have been no reports of casualties or building collapse in Karachi,” he said, adding that tremors might continue for one to two more days before the energy fully settles.
Leghari highlighted Landhi, Malir, and other areas of Karachi as locations with fault activity. Each has a unique seismic profile. Currently, Landhi is the epicenter of recent seismic activity.
He urged citizens to stay cautious, stating, “It’s better to be careful to avoid any inconvenience.” People should remain alert and follow safety guidelines during these minor tremors.
Why do Earthquakes Occur?
Explaining the science, Leghari said earthquakes happen when stress builds up along a fault line – a fracture in the Earth’s crust – and is eventually released in the form of seismic energy.
This release of energy causes the ground to shake, resulting in what we experience as an earthquake. The intensity of these quakes often decreases gradually as the energy dissipates.
Interestingly, the impact of an earthquake is not always felt directly above the fault line.
He gave the example of the 1995 Great Hanshin earthquake in Kobe, Japan. Although Kobe suffered massive destruction, scientists later discovered that the actual fault line was located about 250 kilometers away. This shows that energy released from a distant fault can cause shaking in areas far from its origin.
In a similar context, Karachi lies near several fault zones.
For instance, if the main fault line is located in Landhi, the energy it releases could potentially affect any part of Karachi, not just Landhi itself.
