Blame the collision of plates under the Himalayas for the earthquake or the aftershocks. The weekend was marred by one of the worst tremors in recent times that claimed over 2,000 lives in Nepal and around 50 in Bihar. Piyush Kumar Tripathi decodes the series of earthquakes that shook Nepal and north India:

What has led to such high-intensity earthquakes?

The epicentre of the quake and the aftershocks was around Kathmandu. India Meteorological Department states that almost all major earthquakes in India and its adjoining region occur along the Himalayan range. This is due to the Indian plate's movement in north-north-east direction below the earth's surface and collision with the Eurasian plate along the range. This leads to frequent overlapping of plates on each other, causing repeated earthquakes.

How many aftershocks have been recorded at the epicentre in Nepal?

38 as on 6pm on Sunday but only three of them were felt in Bihar (2 on Saturday and one on Sunday).

How are the tremors reaching from their epicentre in Nepal to Bihar and other parts of the country?

The shallow depth of the earthquake, 10km, at the epicentre allows the tremors to be felt at far-off places like Bihar, Uttar Pradesh, Punjab and Delhi among others. The shallower the depth of the earthquake, the shocks are felt over a wider area.

What was the magnitude of the tremors felt in Patna and other parts of Bihar?

The IMD headquarters at New Delhi or any other earthquake monitoring agency did not release any official figure for the magnitude of tremors felt in Bihar. However, Patna meteorological centre director Ashish Sen claimed that apart from the primary earthquake (7.9 at epicentre), the magnitude of only three aftershocks were more than 5.5 on the Richter scale in Bihar.

Can the scientists or experts forecast earthquakes?

No scientific technique is available anywhere in the world to predict earthquakes with reasonable degree of accuracy with regard to space, time and magnitude.

Has IMD got any equipment (seismometers) to measure the intensity of an earthquake in Bihar?

The state has only one earthquake monitoring station at Valmiki Nagar in West Champaran. However, even that seismometer has been defunct for past several years.

Has the earthquake anything to do with overexploitation of nature by human beings like in the case of climate change or environment pollution?

Though science does not confirm this, claims regarding human-activated seismic activity is being made lately. It is being claimed that too much of human interference is affecting geology of any region. Construction of new dams or mountain-cutting is leading to seismic imbalance, which could be one of the factors behind earthquakes. However, such claims have not been proved yet