Petrinja earthquake – will deputies soon forget that they were escaping from the parliament?
Earthquakes have threatened human lives for millennia. In areas where the earthquake risk is medium to moderate, stronger earthquakes are less common compared to other natural disasters, so unfortunately they often sink into oblivion in the human consciousness. Slovenia is a fairly typical example of such area, which has experienced several strong earthquakes in the past, but they happen only in a few hundred, thousand or even more years. The latter earthquakes in particular are problematic, as we do not have enough good data on them. However, the data we have suggest that if a similar earthquake as the one in Idrija in 1511 (the strongest earthquake evidenced), would occur again we could expect several thousand deaths. In Slovenia 33.4% of the population lives in an area where a devastating earthquake is possible. Individual studies found that less than half of existing multi-apartment buildings meet modern construction requirements. In the area of the Ljubljana region alone, a devastating earthquake would leave 30-70% of the population homeless. According to the latest estimates of experts, the material damage would amount to at least 7 billion Euros (15% of Slovenia’s GDP) and plunge us into an economically catastrophic situation. Many of these challenges can be solved by smart integrated renovation of buildings with natural materials from renewable sources (like wood) and thus we can add to earthquake safety also energy efficiency, positive environmental impact, and the health and well-being of the users of these buildings.
What can we learn from the Croatian case and what the state must do? In the first place, it should take care of the seismic rehabilitation of the most problematic part of the building stock as soon as possible, ie. critical infrastructure. The Medical Center Ljubljana would have survived yesterday’s earthquake (with injuries), but the very old buildings, were many clinics are located (infection clinic, oncology institute, etc.), would have suffered a significantly worse scenario. We should take as a reminder yesterday’s event in Croatia, when a roof of the hospital in Sisak collapsed.
In Slovenia, we have many extremely seismically problematic schools and kindergartens. Again, we should be reminded that yesterday the whole kindergarten in Petrinja collapsed. Due to the holidays season, it was fortunately empty, otherwise the number of fatalities in our neighboring country would have been significantly higher. Even worse, the death tax would be paid by more children.
If we return to Slovenia – if/when our country would be able to exercise sufficient prudence and actually take care of the seismic rehabilitation of its own problematic infrastructure, it should further take care of the renovation of the private building stock. Here we can be inspired by New Zealand or Italy – both countries have experienced earthquakes in the last decade that have caused enormous material damage as well as many deaths. New Zealand is transferring the burden of seismic renovation of buildings to the owners (if the buildings do not meet at least 1/3 of today’s requirements for earthquake resistance). On the other hand, Italy has provided extremely favorable financial assistance to those who opt for a comprehensive renovation of the facilities. Right now we have in Slovenia at our disposal a lot of grants and repayable European funds to stimulate the economy after the pandemic. If at least part of these funds were invested in stimulating comprehensive renovations of facilities, we would be able to take a huge step forward. Not only would we finally start solving the pressing problem of seismic safety, but we would also step away from the mere partial rehabilitation of buildings. So far, this has been limited to energy rehabilitation of buildings, in most cases due to unreasonable requirements and restrictions on the use of European Structural and Investment Fund.
The last lesson of yesterday’s catastrophe from our neighbors is the necessity of speeding up the process of updating the seismic hazard map (which is in progress) and consider more consistent control over construction projects, both in the design phase and construction. The acceleration of the foundation soil due to yesterday’s earthquake in Petrinja was 1/3 higher than the usual project acceleration according to the Croatian map of earthquake danger for this area. This means that the strength of yesterday’s earthquake corresponded to an event that could be expected at the location in question at more than every 1000 years and not 475 years, which is in principle the return period of the project earthquake. In fact, a similarly intense event in Petrinja took place more than 110 years ago. Footage of yesterday’s event also showed the complete demolition of buildings that were built during the period of validity of at least basic earthquake regulations or even later – due to errors in design or implementation control, the buildings were not built properly. And since the Slovenian self-building tradition does not significantly differ from the Croatian one, we can imagine the safety of our newer houses.
Let’s move from lessons to solutions – the Republic of Slovenia’s building stock needs a thorough and comprehensive renovation. Seismic safety is just one of the aspects we need to consider. In order to reduce negative environmental effects caused by construction in general, and in particular to mitigate the speed and intensity of climate change, we need to radically improve the energy efficiency of buildings, with materials and solutions that are as carbon neutral as possible. We also need to renovate buildings to have positive impact on people’s health and well-being. Therefore, if we use as much wood as possible in the renovation of the building stock (and the construction of a new one), we will go quite few more steps further than if we were to undertake only earthquake remediation with classical procedures and materials. Italy has built replacements for residents who lost their homes during the L’Aquila earthquake in 2009 in a multi-storey wooden version. Yugoslavia did the same after the Skopje earthquake in 1963, but the wooden construction at the time was meant to be temporary, and in time it became permanent, therefore it unfortunately acquired the negative connotation of “barracks” over time. Due to the considerable progress of wooden construction, Italians are today extremely satisfied with their modern design. With advanced engineered wood products, buildings can be renovated easily and efficiently, because with their low weight (5 times less than concrete) they hardly increase seismic forces, and at the same time offer high load-bearing capacity. They are also ideal for modular construction, and with such wooden buildings, the state could dynamically regulate housing needs in crisis as well as non-crisis situations. They enable the logistical combination of a set of modular accommodation units that can be used in the event of refugee crises, after natural disasters, as extensions or upgrades of school or hospital facilities, temporary hospitals, etc. The memory of Chinese building a hospital in 10 days in the first wave of the COVID-19 pandemic is still very alive. It is important to know that it could be installed even faster in a light wooden version. It is not necessary to waste words about better living conditions created with wood compared to steel or concrete containers, and on significantly less impact on the environment. With a prudent approach, earthquake problems can be solved and at the same time, capacities for other emergencies can be built, construction and wood processing industry can be promoted, negative environmental impacts can be reduced, human health and well-being can be improved, and the new European funds can be efficiently used.
I hope that the memory of the deputies and the government about the escape from the National Assembly building (which has been basic seismic remediated) will not sink into oblivion too soon. When we look at demolished buildings and rescuers looking for survivors among the ruins in Japan or even southern Italy, such events seem too far away to affect us. This time, however, we were just a shot away from the disaster. Now we have a great opportunity to sort things out and perhaps we are get prepared for the next stronger earthquake that will be with us at some point (and it certainly will be). The will has been around for a long time. Now, funds are also available. After the pandemic, will we be able to renovate the damaged buildings in addition to the damaged relations?