Experts have long been warning of the danger of serious earthquakes in South Asia - and say more are likely.
By Roland Pease
BBC science correspondent
Many have struck along the southern flanks of the Himalayas over past centuries - but not enough to account for all the steady, northward movement of India into Asia.
The earthquake in Pakistan is the result of India's long-term, gradual, geological movement north into Asia at a speed of five centimetres a year - a millimetre per week.
Earthquakes happen when energy stored up along geological faults, like the Himalayan thrust, is suddenly released.
The trouble is, the more time passes without seismic release, the more energy accumulates, making a giant earthquake more likely.
The latest earthquake fits in with the scientists' expectations but, at 7.6 on the Richter scale, is relatively weak compared to what they feared.
Nevertheless, it is likely to have been very destructive - the 2001 earthquake in the western Indian state of Gujurat was of a similar strength and killed 14,000 people.
But earthquakes tens of times more powerful must be expected, the experts warn - and could kill as many as a million on the Ganges plain.
What scientists cannot say is when the next one will strike - and that makes it far more difficult for them to convey their warning.