Strong 6.1-magnitude quake strikes off Indonesia's Java

Jakarta (AFP) - A 6.1-magnitude earthquake struck off Indonesia's main island of Java on Saturday, the US Geological Survey reported, flattening homes and sending panicked residents running onto the street.

Dozens of buildings were damaged, including 16 houses and that collapsed in the town of Banyumas, as well as a mosque that crumbled, National Disaster Mitigation Agency spokesman Sutopo Purwo Nugroho said.

"Authorities are continuing to asses other buildings for damage," he said.

"So far there are no reports of casualties."

People in the town of Adipala near the epicentre said they felt the ground shaking hard for up to 20 seconds, as the quake struck in the sea off the coast of southern Java.

"We all just ran onto the street, there were so many people," Astri, a florist who goes by one name, told AFP by phone from her flower shop.

"But it doesn't seem to have damaged anything around here, and we're getting back to work," she said.

The quake struck 39 kilometres (24 miles) south-southeast of Adipala, according to the USGS. It was felt in several towns up to 50 kilometres from the Javanese coast, including in the more densely populated Yogyakarta city, where at least eight homes were damaged, Nugroho said.

The quake hit at 12:14 pm (0514 GMT) at a depth of 83 kilometres, and Indonesia's meteorology, climatology and geophysics agency said there was no risk of a tsunami.

Indonesia sits on the Pacific "Ring of Fire", where tectonic plates collide, causing frequent seismic and volcanic activity.

A 6.1-magnitude quake that struck Aceh province on Sumatra island in July 2013 killed at least 35 people and left thousands homeless.