The 1755 Lisbon Earthquake

Shaken not stirred

When the late Sir Sean Connery, playing James Bond 007, ordered a vodka martini, he always asked for it to be “shaken not stirred”. Sadly, he passed away last week at the age of 90, but this phrase did inspire me for this headline, coinciding with the government “A Terra Treme” (The earth trembles) earthquake awareness exercise.

We hope that we will never have to experience a major earthquake but, if we do, the action we take in the first few seconds can determine whether or not we become a casualty.

Each day, 10-12 minor earth tremors take place in or around mainland Portugal, the majority off the south and southwest coast of the country. Far more around the Azores.

No need for panic, however, as these are very small, mostly less than 2.5 magnitude on the Richter scale, and are seldom felt. To put this in perspective, there are some one to 1.3 million tremors of this size globally each year. Occasionally, some are a little larger at 3-4 on the Richter scale, but seldom cause any damage at this level.

However, the 1755 earthquake that destroyed most of Lisbon and parts of the Algarve was much larger.

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 200km (120mi) 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.

According to historical records, most of the earthquakes affecting Portugal (mainland) have epicentre southwest of the Iberian Peninsula (Gorringe bank) or in the Lower Tagus Valley. The most vulnerable areas are the Lisbon urban area and Algarve. Major earthquakes occurred in 1531, 1755, 1909 and 1969.

Creating awareness
Basically, in an earthquake, most people die or are injured attempting to leave a building down stairs. Being prepared involves all of us, by creating awareness of the risk and simple life protection measures we can take should an earthquake strike.

Each year, therefore, the Portuguese government, through ANEPC, conducts what is known as the “A Terra Treme” exercise. Last year, over 700,000 people participated by practising “Drop, Cover, Hold On”. Most schools were involved as well as many businesses.

This year, the ANEPC will promote, on November 5 at 11.05am, the eighth edition of the national seismic risk awareness exercise. The date indicated for its realisation coincides with the World Tsunami Risk Awareness Day, an ephemeris instituted by the UN.

This initiative is part of the activities that form part of the National Strategy for Preventive Civil Protection and aims to empower the population to know how to act before, during and after an earthquake, sensitising citizens to the fact of living in a risk society, and challenging themselves to get involved in the process of building safer and more resilient communities.

The exercise comprises the practice of three simple gestures that can make a difference to those who practice them in the face of an earthquake.
The action has a duration of one minute, in which the participants, individually or collectively, are invited to perform the three self-protection gestures: DROP, COVER, HOLD ON.

Be prepared
Reading this, you may feel that this is unlikely to happen, so why bother? But how many of you have earthquake insurance for your home or business? Portugal is one of the higher risk countries; so be prepared.

The ways to do this, according to Civil Protection, include: inquiring about the possible causes and effects of an earthquake in your area; talk about it with your family and friends; make an emergency plan for your family; ensure everyone knows what to do in the event of an earthquake; decide a meeting place in advance in case the family members separate during the earthquake; and prepare your home in order to facilitate the movements, clearing corridors and passageways, arranging furniture and toys.

During an earthquake
Often the instinctive action people take during an earthquake is to try and escape by running to the outside of the property. However, many people die by doing this, from falling or from collapsing structures due to the violence of the shaking.

During an earthquake, if you are indoors in a building, the advice to reduce injuries or worse is as follows: If you are on one of the upper floors of a building, do not rush to the stairs; never use elevators; take shelter in the interior doorway, in the corners of the rooms, or under a table or bed; head to an open location calmly, away from the sea or waterways; keep away from buildings (especially the most degraded, high or isolated), from electricity poles and other objects that may fall on you; get away from slopes, walls, chimneys and balconies that may collapse.

So, unless you are next to an entrance, the safest place is to DROP to the floor, COVER yourself under a table and HOLD ON. Experience has shown that acting calm during an earthquake greatly contributes to minimising casualties.

So, at 11:05 hours this Thursday, whether you are in your office or at home, practice these measures, taking the preparation actions mentioned in this feature.
Comprehensive protection measures and details of earthquakes and tsunamis can be found on and our website under Civil Protection/Earthquakes – Tsunami. This includes protection measures as well as a video we made and an ANEPC online booklet which we translated into English. Safe Communities Portugal is the only official Civil Protection Volunteer Organisation serving the international community in the English language in Portugal.

By David Thomas
|| [email protected]

David Thomas is a former Assistant Commissioner of the Hong Kong Police, consultant to INTERPOL and the United Nations Office on Drugs and Crime.

In 2011, he founded Safe Communities Algarve to help the authorities and the community prevent crime. It is now registered as Associação SCP Safe Communities Portugal, the first national association of its type in Portugal.

913 045 093
[email protected]