WELLINGTON—A 7.7 magnitude earthquake struck the South Pacific region on Thursday, triggering tsunami warnings and calls for residents to avoid beaches and shore areas. The European Mediterranean Seismological Centre (EMSC) said the 7.7 magnitude quake’s epicenter was 258 miles east of Tadine, New Caledonia, and at a depth of 6.2 miles. Australia confirmed a marine tsunami threat to Lord Howe Island, a marine reserve more than 450 miles northeast of Sydney, but said evacuations were not necessary. New Zealand authorities urged residents along its northern coast to avoid beaches and shore areas. The New Zealand National Emergency Management Agency said people should get out of the water, off beaches, and away from harbors, rivers, and estuaries in areas from Ahipara to Bay of Islands, Great Barrier Island, and from Matata to Tolaga Bay. “We expect New Zealand coastal areas to experience strong and unusual currents and unpredictable surges at the …