The East Coast earthquake has snarled travel by air, road and rail around the region. Friday's quake was centered in northern New Jersey and registered a magnitude of 4.8. It shook skyscrapers and suburbs across the northeastern U.S. for several seconds. It caused no major damage but startled millions of people in an area unaccustomed to such tremors. It diverted flights and disrupted travel on roads and rails during runway, bridge, and tunnel inspections. Flights to the Newark, New York and Baltimore airports were held at their origins for a time while officials inspected runways for cracks.