A magnitude 5.1 earthquake struck very close to Pakistan's capital of Islamabad, the US Geological Survey (USGS) said on Friday. Although the quake had a moderate magnitude, its epicentre was only 10 miles (16 km) northeast of the populous city. It struck at 1:59 a.m. on Saturday (2059 GMT on Friday) and was very shallow, only 16.2 miles (26 km) deep, the USGS said. A magnitude 5.1 quake is capable of causing considerable damage.