<Tr> <Th> Max . intensity </Th> <Td> XI (Extreme) </Td> </Tr> <Tr> <Th> Casualties </Th> <Td> 10,000--100,000 deaths </Td> </Tr> <P> The 1755 Lisbon earthquake, also known as the Great Lisbon earthquake, occurred in the Kingdom of Portugal on the morning of Saturday, 1 November, the holy day of All Saints' Day, at around 09: 40 local time . In combination with subsequent fires and a tsunami, the earthquake almost totally destroyed Lisbon and adjoining areas . Seismologists today estimate the Lisbon earthquake had a magnitude in the range 8.5--9.0 on the moment magnitude scale, with its epicentre in the Atlantic Ocean about 200 km (120 mi) west - southwest of Cape St. Vincent . Estimates place the death toll in Lisbon alone between 10,000 and 100,000 people, making it one of the deadliest earthquakes in history . </P> <P> The earthquake accentuated political tensions in the Kingdom of Portugal and profoundly disrupted the country's colonial ambitions . The event was widely discussed and dwelt upon by European Enlightenment philosophers, and inspired major developments in theodicy . As the first earthquake studied scientifically for its effects over a large area, it led to the birth of modern seismology and earthquake engineering . </P>

What was the magnitude of the lisbon earthquake