Early this morning, at 5:11 AM, an earthquake with a magnitude of 5.3 on the Richter scale struck off the coast of Sines, Portugal. The Portuguese Institute for Sea and Atmosphere (IPMA) confirmed that the epicenter was located 58 kilometres west of Sines, at a depth of 10.7 kilometres. This information was further supported by the United States Geological Survey (USGS), which slightly revised the magnitude to 5.4. The Euro-Mediterranean Seismological Center (EMSC) initially recorded the quake as a 5.1 magnitude event at a depth of five kilometres.

The tremor was felt widely, with reports indicating it was noticeable across the Lisbon metropolitan area, including the capital itself, and in the district of Setúbal. Additionally, residents in parts of Spain and Morocco also reported feeling the quake. According to IPMA, the maximum intensity reached IV/V on the Modified Mercalli Intensity scale, which classifies the shaking as moderate to strong. So far, four aftershocks have been recorded.

Fortunately, the IPMA reported that there were no casualties or significant damage resulting from the earthquake. The shaking in the Sines region was most intense, while it was felt more mildly in Lisbon and Setúbal. According to IPMA, an intensity level of IV on the Mercalli scale could cause vibrations similar to those from heavy traffic, with windows, doors, and dishes rattling. At higher intensity levels, walls and wooden structures might creak, and parked cars could sway.

Determining the exact location of an earthquake’s epicenter is a complex process, involving intricate physical and mathematical calculations. Various agencies often provide slightly different results, and preliminary estimates are frequently updated as more data becomes available.

Historical Context: Past Major Earthquakes in the Region

This recent event brings to mind the significant earthquakes that have occurred in Portugal’s history. In 1969, the country experienced the most powerful earthquake of the 20th century, with a magnitude of 7.9 on the Richter scale. The epicenter was located 200 kilometers southwest of Sagres, and the tremor was most strongly felt in the southern regions of Vila do Bispo, Portimão, and Aljezur. Tragically, 13 people lost their lives.

Going back further, Lisbon was nearly destroyed by a catastrophic earthquake in 1755. With an estimated magnitude exceeding 8 on the Richter scale, the quake was followed by a massive tsunami, possibly reaching heights of 20 meters, and devastating fires. Although the exact death toll is unknown, it is believed that at least 30,000 people perished. This disaster struck at a time when Lisbon was a vital commercial and political hub in Europe.

The aftermath of the 1755 earthquake had far-reaching effects, both physically and philosophically. The Marquês de Pombal, then the Prime Minister of Portugal, led the reconstruction efforts, introducing new building regulations designed to withstand future earthquakes and implementing urban reforms that shaped modern Lisbon. The earthquake also influenced European thought, with philosophers like Voltaire and Rousseau contemplating the nature of such tragedies and the societal responses to them.

Earthquake Safety: What to Do Before, During, and After a Quake

Preparing for an earthquake can make all the difference when it strikes. Here’s a comprehensive guide to help you stay safe before, during, and after an earthquake.

How to Prepare Before an Earthquake:

1. Know Your Building: Familiarize yourself with your building’s emergency exits. Know where they are located and how to reach them quickly in case of an emergency.
2. Secure Your Home: Avoid placing heavy mirrors or frames above beds or places where you might seek shelter. Anchor heavy furniture, cabinets, and bookshelves to the walls, floor, or ceiling to prevent them from tipping over.
3. Keep Pathways Clear: Ensure that hallways and exits are unobstructed to allow for a quick and safe evacuation if needed.
4. Create an Emergency Kit: Assemble a kit with essentials like first-aid supplies, a flashlight, water, and non-perishable food. Keep it easily accessible.

What to Do During an Earthquake:

1. Stay Calm: Panic can lead to poor decision-making. Try to remain as calm as possible.
2. Avoid Hazards: Move away from windows, mirrors, and any unsecured furniture or objects that could fall.
3. Find Shelter: Take cover in a safe spot, such as under a sturdy table or bed, or next to an interior wall, especially near structural pillars.
4. Don’t Rush Outside: If you’re indoors, don’t rush for the exit, especially in crowded spaces. It’s safer to stay inside until the shaking stops.
5. Avoid Elevators: Never use elevators during an earthquake, as power outages or damage could trap you.
6. Conserve Energy: Limit physical exertion to save energy for critical actions.
7. Protect Your Head: Drop to the ground and cover your head and neck to protect yourself from falling debris.
8. Stop Machinery: If you’re near any machinery or heavy equipment, stop it immediately and move away from it.
9. Use Phones Sparingly: Use your mobile phone only in case of emergencies to avoid overloading communication networks.

What to Do After an Earthquake:

1. Avoid Ignition Sources: Don’t use lighters or matches, as there might be a gas leak.
2. Turn Off Utilities: As a precaution, turn off the water, electricity, and gas supply to your home.
3. Keep a Fire Extinguisher Nearby: Have a fire extinguisher within reach in case of a fire.
4. Check for Damage: If you suspect structural damage to your building or if anyone is injured, contact the authorities immediately.
5. Stay Safe Outdoors: If you’re outside, move away from buildings and maintain a safe distance from them.
6. Avoid Water Bodies: Steer clear of the ocean or any rivers, as there may be a risk of a tsunami or other water-related hazards.
7. Watch for Electrical Hazards: Stay away from power lines and be cautious of any exposed wires.
8. Switch to 2G Network: If you’re having trouble making calls or sending messages, try switching your phone to 2G to increase your chances of connecting.

By following these steps, you can significantly reduce the risks associated with an earthquake and ensure that you and your loved ones stay safe.