Residents of the village of La Restinga on the island of el Hierro have still not been allowed to return home as a result of continued doubts over the volcanic eruption which is taking place close to the coast of the smallest of the Canary Islands. The offshore eruption, which has caused a stain to spread across the surface of the ocean, began last Thursday after several weeks of seismic activity. The stain is mainly caused by sulphur expelled from an underwater crater, believed to be around a meter in diameter, which is around 130 meters below sea level. Recent discoveries have also seen pumice stone floating on the surface of the sea, indicating that the crater may be wider than first imagined. Authorities evacuated residents of La Restinga, the village closest to the eruption, last week and it had been thought they would be allowed to return to their homes on Monday, all be it just for a short while in order to collect possessions left behind in the rush to abandon the village. However, their return was delayed as a result of the strong smell of sulphur in the region, which could have affected the population. The smell is thought to have occurred as tides carry the sulphur stain closer to land as the volcano continues its eruption. Spanish government scientists continue to investigate the eruption and on Sunday the co-ordinator of the scientific team, Ramon Otriz gave the first conclusions of the study, saying there would be four stages, which could eventually see the.. \"the creation of a small island from which a flow of lava could spread.\" The Canary Islands\' regional government raised the level of alert over the eruption to \'level red\' on Sunday.