A 7.7 magnitude earthquake struck off the Sanriku coast at 4.53pm on Monday Get Travel Insider with Simon Calder. A newsletter packed with tips, deals, inspiration, and the latest travel news Get the Travel Insider newsletter with Simon Calder Get the Travel Insider newsletter with Simon Calder Email * SIGN UP I would like to be emailed about offers, events and updates from The Independent. Read our Privacy notice Travellers have been told to “remain vigilant” after a magnitude 7.7 earthquake