A powerful quake measuring 7.8 on the Richter scale has hit Honduras in the Caribbean Sea, triggering a tsunami warning for nearby shores, the US Geological Survey (USGS) said.The northern coast of Honduras closest to the quake's epicentre is sparsely populated. There were no early reports of injuries or damage on the land, Xinhua news agency reported.Tsunami waves were possible on coasts in Mexico, Jamaica, Honduras, Cuba, Costa Rica, the USGS said.A tsunami advisory by the Pacific Tsunami Warning Centre was in effect for Puerto Rico and the US Virgin Islands. Possible one-metre-high waves were expected.