Two tremors hit Saudi volcano region, no injuries

RIYADH, May 19 (Reuters) - Two medium-size earthquakes hit a volcanic region in northwestern Saudi Arabia on Tuesday, but there were no injuries and no damage to buildings, a seismological official said.

A 5.4 earthquake hit the northwestern region in al-Ais on Tuesday, just hours after a 4.8 tremor, said Ahmad al-Attas, vice-president of the Saudi Geological Survey (SGS).

Authorities had evacuated villages on a 20-km (12-mile) radius from al-Ais volcano after a previous tremor on Sunday.

The region is 240 km away from the holy city of Medina and 150 km away from the port of Yanbu on the Red Sea. It is not close to the world's top oil exporter's oil and petrochemical facilities in Rabigh.

SGS President Zuhair Nawab said the region lies on a fault line, declining to comment on current magma levels, but newspapers reported that in the past few days magma levels had risen to 4 km (2.5 miles) below the surface from 8 km.

Fears of an eruption in dormant volcanoes in al-Ais sent panic stricken residents voluntarily fleeing to Medina and Yanbu last week.

Lava from al-Ais volcanoes has never spread out beyond 18 km, said Nawab, adding that the last volcanic eruption there was over 700 years ago.

The population of al-Ais, an ancient resting place for caravans travelling between the western and southern cities of the Arabian Peninsula and Syria, is estimated at around 60,000. (Reporting by Asma Alsharif; Editing by Jon Hemming; Riyadh newsroom, +966 1 463 2603,