REYKJAVIK (Reuters) -A volcanic eruption in Iceland that had threatened to engulf a seaside town appeared to subside on Tuesday, although authorities and geologists warned that danger still persisted. A flow of red-hot lava on Sunday reached the outskirts of Grindavik, a fishing town of some 4,000 residents, setting three houses ablaze but causing no harm to people who had been evacuated for a second time since November. Live footage on Tuesday morning no longer showed signs of molten rock erupting from the ground, even as experts warned that new fissures could emerge at short notice. The Icel…