By Catarina Demony
LISBON (Reuters) - Authorities on a mid-Atlantic Portuguese island hit by thousands of small earthquakes in recent days started evacuating people living at the bottom of coastal cliffs on Thursday as fears of a stronger tremor or a volcanic eruption grow.
Since Saturday, over 2,000 earthquakes, with a magnitude of between 1.6 and 3.3, have been recorded on the volcanic island of Sao Jorge in the Azores archipelago, according to the region's CIVISA seismo-volcanic surveillance centre.
The small quakes, which have caused no damage so far, were reported along the island's volcanic fissure of Manadas, which last erupted in 1808. A big earthquake hit the island in 1980, causing severe damage.
CIVISA has raised the volcanic alert to level 4 out of 5, meaning there is a "real possibility of eruption", and said the number of earthquakes was above normal levels.
Those in hospital or in care homes in the municipality of Velas, which is likely to be the most affected area, have already been transferred to Calheta on the other side of the island.
The mayor of Velas, Luis Silveira, said on Wednesday plans to evacuate the rest of the population to Calheta or to other islands would only be activated if needed.
A spokesperson for the municipality told Reuters those living in the island's so-called "fajas", small plains originally created by lava or landslides at the bottom of cliffs, would be preventively evacuated. There are around 40 "fajas" in Sao Jorge.
The evacuation comes after the Azores archipelago activated its emergency plan.
Sao Jorge, one of nine islands that make up the Azores, is home to about 8,400 people and is part of the archipelago's central group, which includes the popular tourist destinations of Faial and Pico, which are also volcanic.
Azores President Jose Manuel Bolieiro visited Sao Jorge on Thursday morning, and said "everything was prepared" to evacuate people, adding the government was also working to increase the number of commercial flights.
Authorities have told residents where to go in case of need, and said alerts would be sent to the population using social media, the local radio station and by ringing the island's church bells.
(Reporting by Catarina Demony; Editing by Nathan Allen and Jonathan Oatis)