By Catarina Demony
LISBON (Reuters) - Authorities on a mid-Atlantic Portuguese volcanic island hit by thousands of small earthquakes in recent days are drawing up plans to evacuate people in case the situation worsens.
Since Saturday, about 2,000 quakes have been recorded on Sao Jorge in the Azores archipelago, Luis Silveira, mayor of the municipality of Velas, told reporters.
There are fears the earthquakes, with a magnitude of between 1.6 and 3.3, could trigger a stronger tremor or a volcanic eruption, according to the region's CIVISA seismo-volcanic surveillance centre.
CIVISA has raised the volcanic alert to level 4 out 5, meaning there is "real possibility of eruption", said Clelio Meneses, the regional secretary responsible for the Civil Protection authority. "What we are doing is preparing for the worst case scenario," Meneses said.
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.
Silveira said those in hospital or in care homes in Velas were being transferred to Calheta on the other side of the island. He said civil parishes in Velas were also preparing to transfer those with reduced mobility.
Plans to evacuate the rest of the population to Calheta or to other islands would only be activated if needed, he said.
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.
"We recommend that people have a backpack prepared with the bare minimum, such as a change of clothes, medication and some food," Silveira said.
He said the military and air force were prepared to help and that a navy vessel was on its way. The Portuguese Red Cross is sending beds to the island.
The sudden increase in seismic activity is reminiscent of the earthquakes detected before the eruption of the Cumbre Vieja volcano on Spain's La Palma island last year, some 1,400 km (870 miles) southeast of the Azores.
(Reporting by Catarina Demony; Editing by Nathan Allen, Janet Lawrence and Grant McCool)