ISTANBUL — A 6.2-magnitude earthquake struck off the coast of Istanbul on Wednesday, according to Turkey’s Disaster and Emergency Management Agency (AFAD).The quake occurred off Silivri, to the westISTANBUL — A 6.2-magnitude earthquake struck off the coast of Istanbul on Wednesday, according to Turkey’s Disaster and Emergency Management Agency (AFAD).The quake occurred off Silivri, to the west