SANTIAGO, Nov 14, 2007 (AFP) - A strong earthquake measuring 7.7 rocked arid northern Chile Wednesday, killing at least two people, injuring others, sparking panic and causing power outages.

Authorities said two women, one aged 88 and the other 54 died when they were crushed under collapsing walls in the city of Tocopilla, 1,600 kilometers (1,000 miles) north of Santiago, doctors said.

Local authorities said at least 45 people were injured, but media reports put the figure at about 100.

'It is a major quake,' Fernandez said of the temblor that struck at 12:43 pm (1543 GMT.)

The epicenter was located 1,260 kilometers (783 miles) north of the Chilean capital Santiago. It was felt as far away as Bolivia's capital, La Paz, high in the Andes to the northeast.

Images from Chile's TVN television showed cars crushed by debris, and frightened people running onto the streets as the quake struck.

Damage was also reported in the northern cities of Calama and Arica which lost electrical power.

The government said a plane loaded with humanitarian aid was scheduled to fly to the affected area later in the day.

The US Geological Survey said the quake measured 7.7 on the moment magnitude scale,

which measures the amount of movement on the underground fault and the area of the fault that ruptured. Many seismologists now use that system rather than the Richter scale that measures an earthquake size based upon the amount of ground shaking.

A measurement of seven indicates a major quake and eight a great quake.

Authorities initially warned the quake could cause a tsunami but later lifted the warning, saying the epicenter was too far from the Pacific coast.

Meanwhile separate earthquakes also hit Argentina and Central America on Wednesday.

An earthquake, which US geologists measured at magnitude 5.3, rocked Guatemala and neighboring El Salvador, with no reports of casualties.

That quake was not related to the one in Chile, the United States Geological Survey said.

'There's no link between the ones in Guatemala and Chile other than they're occurring in the Pacific rim region,' John Bellini, a geophysicist at the USGS, told AFP. 'They're not related. Nothing triggered the other or anything like that.'