A massive 7.9 magnitude earthquake has struck eastern Japan, just hours after a 7.3 magnitude earthquake struck. Tokyo's two main airports, Narita and Haneda, are closed to flights.
Strong aftershocks are also being reported from the Tokyo area, and a 6-metre tsunami is reported to have hit port and coastal areas, including the city of Kamaishi in Iwate Prefecture.
Passengers in airplanes on the ground at Narita Airport reported that the earthquake "felt like really bad turbulence, but [the plane was] not moving".
Inside the airport, a passenger reported Terminal 1 "halls shaking like crazy".
Narita Airport -- the destination for most international flights -- is some 60 km east of Tokyo's centre. That's in the direction of the epicentre of the earthquake, reported to be in Miyagi Prefecture according to Japan's Daily Yomiuri newspaper.
Smaller Haneda airport, some 15 km south of the city, is also closed.
Social media messages from passengers on the ground say, all tweets or updates verbatim:
@serkantoto: At Tokyo Narita airport Terminal 1. Big, HUGE earthquake, halls shaking like crazy. #kowai
@JoelGabrielMA Just sat through an earthquake while on 747 at Narita Airport in Tokyo. Felt like really bad turbulence, but not moving
@JeansNow Wow, big earthquake while on the Narita Express, they had to stop the train. Still swaying from side-to-side.
@elche571 Cabin crew at Narita airport just called me, 7.9 magnitude earthquake, the airport shook like a leave, a lot of panic
@Vera308 wow Id never had sucha big earthquake!! D: and I was at the bathroom of the airport!! but am still alive!!
@er7rookie I'm in the limo to the airport. Really huge earthquake on the bridge!!!! I'm worry about everything and Japan
More coverage of the Tokyo earthquake and tsunami:
About John Walton
Aviation journalist and travel columnist John took his first long-haul flight when he was eight weeks old and hasn't looked back since. Well, except when facing rearwards in business class.