‘Unfortunately nobody can predict the next earthquake’
On Monday morning August 26 at 05.11 the country was startled by an earthquake 58 kilometres west of Sines, in the district of Setúbal with a magnitude of 5.3 on the Richer scale. No personal or material damage was reported, although there were many phone calls from concerned people seeking information.
According to the National Emergency and Civil Protection Authority (ANEPC) in Oeiras, the earthquake had its epicentre at sea but no tsunami warning was given since the magnitude was less than 6.1.
The tremor was felt in several parts of the country but with greater intensity in Setubal and Lisbon.
‘Although this earthquake can be considered as moderate, one shouldn’t worry too much as the southern part of the country has always been seismic active’, says Joao Duarte, seismologist at IPMA, the Portuguese Institute of the Sea and Atmosphere. But it definitely serves as a wake-up call to invest in risk reduction.
It has to do with two tectonic plates pushing against each other. The African plate moves northwest and lifts the Eurasian plate, which is moving to the east – along the so-called Azores-Gibraltar fracture.
The earthquake has been classified as the biggest felt in Lisbon since 1969, which had a force of 7.9 and its epicentre 250 km away from Lisbon. That time 13 people died.
The by far biggest terramoto was in 1755, with a magnitude of 9 on the Richter scale. It developed apocalyptic proportions and completely whipped out the lower part of Lisbon. In memory of that country’s main natural disaster, an Earthquake Museum (Museu do Terramoto) was recently opened in Belem.
The mayor of Lisbon, Carlos Moedas, declared that ‘the City Council has been ‘seismically’ assessing more than 1500 municipal buildings over the last two years and that only 10% of the buildings need anti-seismic reinforcement.’
However, almost 70% of Lisbon’s buildings were built before the seismic protection law in 1983, making the capital the second city with the highest seismic risk after Istanbul.
The weekly newspaper Expresso published, that 195,000 Lisbon residents live in homes that were not built to earthquake standards.
Mafra, says the newspaper, is the only municipality on the mainland that has a special ‘escape plan’ for the population in case of such a natural disaster.’
One can only hope not to be surprised by bigger earthquakes than the one that woke many of us up on that early morning of August 26.
Enjoy your week Approveite a semana (pic Público/Sapo)
‘This earthquake can be considered as moderately severe’, says Fernando Carrilho, chief seismologist at the IPMA (Portuguese Institute of the Sea and Atmosphere). ‘People shouldn’t worry too much as the southern part of the country has always been seismic active.’
‘Preventive measures are warranted’, especially in the densely populated areas in the south – like Lisbon and the Algarve – that are most at risk’, says Daniel Oliveira, a civil engineer at the University of Minho. ‘Although a law from 1958 requires earthquake-proof construction, most buildings in the historic capital date from before that time and there is hardly any monitoring of the implementation of the law.’
Over the past 500 years, Portugal has suffered four major earthquakes – in 1531, 1755, 1909 and 1969 – with a magnitude of 6 or more on the Richter scale. The biggest and by far most tragic one was in 1755. With a magnitude of 9 on the Richter scale, it developed apocalyptic proportions and completely wiped out the lower part of the capital. This earthquake (terramoto) inspired poets, influenced philosophers, activated prophets and motivated politicians – like the Marquis of Pombal – to a completely new architectural reconstruction of the Baixa, Lisbon’s city center.