6.4 magnitude quake off western Mexico: US seismologists

CABO SAN LUCAS, Mexico (AFP) - A 6.4 magnitude earthquake struck Saturday off the coast of Mexico in the Gulf of California, posing a risk of local tsunamis, US seismologists said.

But Mexican authorities said there were no immediate reports of damage or casualties from the quake.

"We have no reported damage in any public building or residences, and hotel managers told me they had no damage at all," the civil protection chief in Loreto, Mexico told AFP.

The coastal town, which is popular with US and Canadian tourists, is located about 89 kilometers (55 miles) from the quake's epicenter, according to Mexican authorities.

The US Geological Survey placed its epicenter about 74 kilometers (46 miles) southwest of Etchoropo, Mexico.

The USGS initially reported that the quake had a magnitude of 6.8 but downgraded it to 6.4 on the Moment magnitude scale. Mexico's national seismology service put the magnitude at 6.3.

Before the downgrade, the Pacific Tsunami Warning Center issued a bulletin ruling out a threat of a "destructive widespread tsunami." But it cautioned: "Earthquakes of this size sometimes generate local tsunamis that can be destructive along coasts located within a hundred kilometers of the earthquake epicenter." "Authorities in the region of the epicenter should be aware of this possibility and take appropriate action," it warned.

The US Geological Survey said the quake struck in the Gulf of California at 1755 GMT at a depth of about 10 kilometers (6.2 miles.)