At least 46 people are killed as a strong quake rocks a remote, mountainous region of the south Asian country.
It was felt as far away as the Indian capital of New Delhi, hundreds of miles to the east, where buildings shook.
Reports said the earthquake was so powerful that it caused the seabed to rise and create a small island about 600 meters (yards) off Pakistan's Gwadar coastline in the Arabian Sea.
The uplift, which is said to have created an island up to 40ft above sea level, occurred despite the spot off the coast being nearly 200 miles from the epicentre.
Early reports said dozens had died, but many of the buildings in that part of the country are made of weak materials and there were fears of more casualties.
Abdul Qadoos, deputy speaker of the Balochistan assembly, told Reuters that at least 30% of houses in the impoverished Awaran district had been destroyed.
The United States Geological Survey issued a red alert for the quake, warning that heavy casualties were likely, based on past data.
Tremors were felt across the province as well as in the sprawling port city of Karachi, residents said. People in Ahmedabad in India, hundreds of miles from the epicentre, ran out of buildings and into the street.
A senior Pakistani meteorologist, Muhammad Riaz, told Dunya TV station it was a "major" earthquake and "heavy destruction" was likely.
Local officials said helicopters to the areas affected.
Office workers in Karachi rushed out of their buildings and sat on the footpaths along the roads or stood away from structures.
Noor Jabeen, a 28-year woman working for an insurance company, said: "My work table jerked a bit and again and I impulsively rushed outside."
In 2005, a 7.6 magnitude quake centred in Kashmir, in a remote north eastern region of Pakistan, killed at least 73,000 people and left several million homeless in one of the worst natural disasters to hit Pakistan.