About one-eighth of buildings in the quake-hit Spanish city of Lorca were severely damaged including 17th-century structures, the regional authority said Saturday.

A preliminary assessment based on inspections by engineers lists the buildings as strictly off-limits, the Murcia regional government said on its website.

"Buildings that have a red color marked on their entrances mean there is some kind of structural damage and that access is prohibited for the moment, although that does not mean they should necessarily be demolished," it said.

Wednesday's 5.1-magnitude earthquake struck at a depth of just 10 kilometres (six miles), killing nine people and wounding at least 100.

The country's deadliest quake in recent memory damaged some 20,000 buildings including many from the 16th and 17th centuries in Lorca, which traces its history back more than 2,000 years.

Between 7,500 and 11,000 city residents of a total population of 92,700 are without lodgings, local dailies El Pais and Publico reported.

A tent village was put up Thursday to shelter the newly homeless, mostly migrant workers from Latin America and Africa with no friends or relatives to take them in, the reports said.

In late February, Spanish seismologist and president of the Official Geological College Luis Suarez predicted a deadly earthquake "shortly," identifying the southern Murcia and Andalucia regions as a danger zone.

He said that statistically Spain has been hit by a major destructive earthquake every 70 years.

But it has been 127 years since the last big one struck in 1884, claiming 900 lives.