WELLINGTON: New Zealand has issued a tsunami warning for southern coastal areas on Monday, following a strong 7.4 earthquake near the South Island city of Christchurch. 7.4 magnitude earthquake shakes New Zealand’s Christchurch “A tsunami is possible,” the national civil defence organization – which is in charge of New Zealand’s emergency management – said in a bulletin. “The first wave activity may not be the most significant,” it said, “though, the tsunami activity would continue for several hours.”