A tsunami warning has beenissued in Far East Russia after a series of powerful earthquakes struck Japan on Monday, authorities in multiple Russian regionsannounced.In the Primorye region city of Vladivostok, located on the coast of the Sea of Japan, authorities said they expect waves to reach 30 centimeters by Monday evening and urged fishing vessels to return to shore.Nakhodka, another city in the Primorye region,issued a dragnet alert and triggered warning sirens, but stressed that residents were not in danger due to the waves, which were expected to reach 57 centimeters.A similar tsunami alert wasissuedby the emergency authorities in the neighboring Khabarovsk region.In a since-deleted post on social media, the Sakhalin regions Emergency Situations Ministry branch said its coastal population was being evacuated to safety.Everyone located in the coastal part of the Tatar Strait [which separates Sakhalin island from mainland Russia] should immediately seek refuge at heights 30-40 meters above sea level, the ministry said on the Russian social network Vkontakte.Authorities latertold state-run news agencies that the evacuation had been called off since the waves were not expected to reach more than 50 centimeters.A powerful earthquake with an estimated magnitude of 7.6 struck western Japan on Monday, triggering tsunami warnings along the length of the country's western coastline and prompting evacuation orders for residents.The initial more powerful quake was followed by a rapid succession of 21 quakes registering a magnitude of 4 or stronger.Japanese weather agencies warned that waves up to five meters in height could reach coastal communities, with 1.2-meter waves already reaching some areas by early Monday afternoon.More than 36,000 households had lost power in some parts of western Japan, according to utilities provider Hokuriku Electric Power.