Japan鈥檚 northern Pacific coast was hit by small tsunami waves on Sunday following a 6.9-magnitude offshore earthquake.
The first tsunami hit the northern city of Miyako at 5:37pm (0837 GMT), but it was so small that the Japan Meteorological Agency said it could not measure its size.
Later, ports in Kuji and Ofunato, located in the same region, saw waves as high as 20 centimetres (less than eight inches), while smaller waves reached other ports in Iwate, the meteorological agency said.
The quake struck around 5:03pm (0803 GMT) in waters off Iwate, according to the Japanese agency which initially estimated its strength at magnitude 6.7 but later revised it to 6.9.
The US Geological Survey measured the quake as magnitude 6.8.
The Japan Meteorological Agency had issued an advisory for a possible tsunami before lifting it shortly after 8:00pm (1100 GMT).
The original quake was followed aftershocks at magnitude between 4.6 and 6.3, the agency said.
Six other offshore quakes hit the same region earlier on Sunday, but were barely felt on land and did not prompt tsunami advisories.
The area may see stronger quakes particularly in the next several days, warned Masashi Kiyomoto, an earthquake and tsunami official at the meteorological agency.
鈥楾his is an area that has seen a series of seismic activities. It is possible that larger earthquakes will occur,鈥� he told a televised briefing.
The region is haunted by the memory of a massive 9.0-magnitude undersea quake in 2011, which triggered a tsunami that left around 18,500 people dead or missing.
That tsunami also sent three reactors into meltdown at the Fukushima nuclear plant, causing Japan鈥檚 worst post-war disaster and the world鈥檚 worst nuclear accident since Chernobyl.
Japan sits on top of four major tectonic plates along the western edge of the Pacific 鈥楻ing of Fire鈥� and is one of the world鈥檚 most tectonically active countries.
The archipelago, home to around 125 million people, experiences around 1,500 jolts every year.
The vast majority are mild, although the damage they cause varies according to their location and depth below the Earth鈥檚 surface.
