Concepcion, Chile's second largest city, is no stranger to devastation, with a history that has been marked by earthquakes.

The country lies on the "Ring of Fire", the line of frequent quakes and volcanic eruptions that circles virtually the entire Pacific rim.

It is one of the most seismically active areas on the planet. Since 1973, there have been 13 events of magnitude 7.0 or greater.

Founded as a military settlement in 1550 north of the Bio Bio river, at a site now known as Penco, Concepcion was overrun and destroyed in 1554 and 1555 by Mapuche armies during the Arauco War in the early period of Spanish colonialism.

It became an important government stronghold during Spanish colonial times, but after earthquakes and tsunamis razed the city no less than five times between 1570 and 1750.

After a huge tremor in 1751, the city was moved from its original site to a location further from the sea in the Mocha Valley - 515 km (320 miles) south of the capital Santiago.

Curfew

Concepcion still rests on a seismically active area, and most of the city was destroyed by a violent earthquake in 1939.

It was also badly affected by the devastating earthquake of 1960 - which with a magnitude of 9.5 was the world's strongest quake. It triggered tidal waves and volcanic eruptions, leaving 1,655 dead and two million homeless.

Saturday's magnitude 8.8 quake occurred at a depth of about 35km (20 miles) below the sea between the Nazca and South American tectonic plates - the vast slabs of the Earth's surface that grind past each other at a rate of about 80mm per year.

Following the quake, the city's estimated one million residents are under curfew, and the army has been brought in to help police who are struggling to control looting in the city.

There is no drinking water in the city, which remains essentially cut off from the rest of the country.