The 1755 Lisbon earthquake, also known as the Great Lisbon Earthquake, was a megathrust earthquake

Megathrust earthquake

Megathrust earthquakes occur at subduction zones at destructive plate boundaries , where one tectonic plate is forced under another. Due to the shallow dip of the plate boundary, which causes large sections to get stuck, these earthquakes are among the world's largest, with moment magnitudes ...

 that took place on Saturday 1 November 1755, at around 9:40 in the morning. The earthquake was followed by fire

Fire

Fire is the rapid oxidation of a material in the chemical process of combustion, releasing heat, light, and various reaction products. Slower oxidative processes like rusting or digestion are not included by this definition....

s and a tsunami

Tsunami

A tsunami is a series of water waves caused by the displacement of a large volume of a body of water, typically an ocean or a large lake...

, which almost totally destroyed Lisbon

Lisbon

Lisbon is the capital city and largest city of Portugal with a population of 545,245 within its administrative limits on a land area of . The urban area of Lisbon extends beyond the administrative city limits with a population of 3 million on an area of , making it the 9th most populous urban...

 in the Kingdom of Portugal

Kingdom of Portugal

The Kingdom of Portugal was Portugal's general designation under the monarchy. The kingdom was located in the west of the Iberian Peninsula, Europe and existed from 1139 to 1910...

, and adjoining areas. Seismologists today estimate the Lisbon earthquake had a magnitude in the range 8.5–9.0 on the moment magnitude scale

Moment magnitude scale

The moment magnitude scale is used by seismologists to measure the size of earthquakes in terms of the energy released. The magnitude is based on the seismic moment of the earthquake, which is equal to the rigidity of the Earth multiplied by the average amount of slip on the fault and the size of...

, with an epicenter

Epicenter

The epicenter or epicentre is the point on the Earth's surface that is directly above the hypocenter or focus, the point where an earthquake or underground explosion originates...

 in the Atlantic Ocean

Atlantic Ocean

The Atlantic Ocean is the second-largest of the world's oceanic divisions. With a total area of about , it covers approximately 20% of the Earth's surface and about 26% of its water surface area...

 about 200 km (120 mi) west-southwest of Cape St. Vincent

Cape St. Vincent

Cape St. Vincent , next to the Sagres Point, on the so-called Costa Vicentina , is a headland in the municipality of Sagres, in the Algarve, southern Portugal.- Description :This cape is the southwesternmost point in Portugal...

.