Experts said the 1755 quake, one of the most powerful in history, and the 2004 South Asian tsunami underscored the need to incorporate scientific advances in building earthquake- resistant cities.
"The earthquake can’t be avoided, but the tragedy can be," Portuguese President Jorge Sampaio told an international conference on the quake.
Salvano Briceno, director of the UN’s International Strategy for Disaster Reduction, said the devastation caused by the Asian tsunami, last month’s Pakistan earthquake and recent hurricanes that hit the United States could have been mitigated by better city planning and modern construction methods.
"Reducing disaster risk cannot only be a political and academic issue. It has to be part of our everyday concern," Briceno told the 200 engineers, scientists and historians at the conference.
Church bells began ringing across the Portuguese capital at 9:30 a.m. (0930 GMT), 250 years to the minute after the earthquake struck Lisbon. With an estimated magnitude of 8.75, the quake and its tsunami killed up to 70,000 people.
The Lisbon quake, which triggered a tsunami felt from Norway to North America, sent shockwaves through Enlightenment Europe and changed forever the way earthquakes were perceived and handled. It was the first quake for which a scientific explanation was sought.
The quake levelled churches filled with worshippers for All Saints Day, one of the major Catholic festivals, and devastated Morocco.
In one conference paper, Robert Muir-Wood, head of research at California’s Risk Management Solutions, estimated that if Lisbon’s earthquake took place today it would cause 100 billion euros ($120 billion) in economic damage.
As the bells tolled, Cardinal Jose Policarpo celebrated a memorial mass in Lisbon’s Carmo Convent, left roofless by the quake. The Christian life, he told about 200 worshippers, "is necessarily marked by suffering", Lusa news agency quoted him as saying.