They usually last for a few short moments, but earthquakes can be calamitous, causing mass human fatalities and the collapse of vital infrastructure, with the threat of secondary perils and deadly tsunamis.
Here are the dangers earthquakes pose and the steps businesses can take to mitigate their impact.
The devastating twin earthquakes which struck Turkey and Syria hours apart in February 2023 affected 11 cities and caused the deaths of more than 55,000 people. For Turkey, it was the biggest such event in 500 years. A few months later, in September, an earthquake rocked the Atlas Mountains and Marrakech in Morocco, killing 3,000 people. In Italy, hundreds of tremors hit the region west of Naples, including a 4.2 magnitude earthquake at the end of September. Then in October, more than 2,400 people died when three earthquakes struck Afghanistan’s Herat province.
Around the world, there are estimated to be half a million detectable earthquakes every year, with 100 of them causing damage. According to recent data, earthquake/tsunami is the No. 5 cause of natural catastrophe loss, accounting for 6% of natural catastrophe claims by total value.
Along with a tragic toll on human life, earthquakes carry enormous financial costs. The economic losses from the Turkey-Syria earthquake are estimated to be around $91 billion, with the Insurance Association of Turkey pegging total losses to the private insurance sector at TRY76 billion ($4 billion). The public Turkish Catastrophe Insurance Pool has received nearly 600,000 claims, with total payments expected to reach TRY29.5 billion ($1.6 billion).
Those losses are significant, but by comparison, the 2011 Tohoku earthquake and tsunami in Japan – believed to be the most expensive natural disaster in history by economic losses ($360 billion) – incurred $47 billion insured losses, while the 1994 Northridge earthquake in the US totaled insured losses of $31 billion (sums adjusted for inflation in 2022). Estimated claims costs arising from the 2010-2011 Canterbury sequence of four earthquakes in New Zealand are believed to be more than $22 billion.
There is currently no reliable technology to predict when and where an earthquake will strike in Turkey, one of the most seismically active countries in the world. By understanding the hazard and designing in earthquake resilience, businesses can reduce the potential damage to buildings and save lives.
While seismic models are not predictions, they can tell us how often, on average, an earthquake of certain characteristics can happen in any given city or area. At our company’s earthquake and fire testing and training center, an extensive facility in Istanbul, a team of researchers use “shaking tables” to simulate the structural and non-structural damage earthquakes can wreak, along with hands-on training, helping to raise public awareness of what to expect when one strikes.
Earthquakes cannot be prevented, but we can learn how to live with them. People are never ready for that moment when the floor begins to shake beneath their feet. It’s like being on a moving bus which suddenly brakes, and you’re thrown forward.
Hazard, Exposure, and Vulnerability
As with other natural perils, the risk for earthquakes consists of three elements: hazard, exposure, and vulnerability. The hazard in this case is the probability of an earthquake happening, which doesn’t vary significantly over the long term, while the exposure represents your assets – your buildings and their contents, for instance. The vulnerability is how likely those assets are to suffer a loss, such as how likely a building is to sustain damage from, say, a magnitude 7.0 earthquake happening at a certain distance.
Growing urbanization increases exposure to earthquakes because it increases the number of vulnerable buildings. Vulnerability depends heavily on local building codes and enforcement. If new buildings are designed and constructed following modern seismic regulation, risks can be limited and even mitigated by retrofitting older structures which were not built according to modern codes.
In the recent Morocco earthquake, much of the observed devastation occurred because many buildings were built using adobe or some other type of unreinforced masonry. These buildings are known to perform poorly in earthquakes, but because they are cheaper to build, they are common in earthquake-prone regions in developing countries.
A change in building usage can also heighten risk. If a building is converted from residential occupancy to commercial premises, it can change the loads in a structure – a warehouse is likely to carry a heavier load than an apartment, for example, and there could be modifications to the building’s structure, such as the removal of walls to create space. Weighty solar panels might be added to the roof. All these factors increase vulnerability to earthquake damage.
Beware of the Secondary Peril
Earthquake risks do not begin and end with the ground shaking. Secondary perils such as landslides, tsunamis, and liquefaction – when the soil behaves more like a liquid than a solid during an earthquake – must all be mitigated where possible.
Different types of soil can amplify an earthquake’s waves, leading to more damage for certain types of building. We have seen this in Mexico City, where the deep, soft soil contributed to earthquake devastation in the past. Cities built on sandy ground are particularly vulnerable to liquefaction, as was experienced after the Christchurch earthquake in New Zealand in 2011. Coastal cities are prone to tsunami risk, as was experienced by Lisbon after the historic earthquake of 1755.
Earthquakes are not caused by the weather. However, climate change could affect the probability of secondary perils occurring, such as landslides in a region that has become drier or wetter due to climate change, or liquefaction, which is dependent on the height of the water table. Over time, rising sea levels could introduce the threat of tsunamis to locations that have never faced this hazard before.
Fires are a particular hazard following earthquakes, with potential gas leaks, the release of hazardous materials, damage to power plants, and explosions posing physical and environmental threats. Human health is also vulnerable to insanitary living conditions, the breakdown of essential utilities like power, water and communication, the lack of shelter, and sometimes criminal activity.
Businesses and Buildings Most at Risk
Although the quality of construction and urban planning are key to reducing the impacts of earthquakes, certain businesses and premises face heightened risks.
Hospitals and healthcare facilities need to remain operational during and after an earthquake. Damage to these can compromise patient care and response efforts. Schools and universities damaged during an earthquake could lead to the disruption of teaching and potential harm to students and staff.
Older buildings made from unreinforced masonry, such as brick or stone, are vulnerable. They lack the reinforcement to withstand shaking and are more likely to be damaged or collapse. With tall buildings, the shaking effect is amplified, and their complex structural dynamics make them more susceptible to structural failure.
Industrial facilities such as factories, chemical storage facilities, and power plants, can also face greater risks during earthquakes. Damage to equipment, pipelines, and storage tanks can lead to hazardous leaks and fires. Buildings under construction could face collapse if the structural elements which resist earthquakes are not in place.
Businesses that depend on transport or communication infrastructure, such as logistics companies and data centers, can face disruption to operations if infrastructure like roads, bridges, and communication networks are damaged. Other vulnerable businesses include shops, tourist and hospitality companies, and financial institutions.
Leading Cities for Resilience
Any city close to the border of a tectonic plate is exposed to high earthquake hazard. This includes the Pacific Ring of Fire (with cities such as Seattle, San Francisco, Los Angeles, Mexico City, Santiago de Chile, Tokyo, Jakarta, and Manila), where around 90% of the world’s earthquakes occur. Many cities in Europe and along the Mediterranean have a relatively high earthquake hazard, especially in Italy, the Balkans, Greece, Turkey, and the Middle East. Wellington and Christchurch in New Zealand are prone to earthquakes, and Himalayan cities, like Kathmandu, are also vulnerable.
Chile, Japan, the US, and New Zealand have some of the strictest building norms and highest levels of public education in earthquake response. Colombia and Nepal have made progress in improving the seismic resistance of their built environments in recent years, while Costa Rica’s seismic code has led to relatively low levels of damage in large earthquakes, as evidenced by the 2012 Samara earthquake (Mw7.6), which resulted in only two fatalities. Similar earthquakes in other regions have been much deadlier – a Mw7.1 earthquake in Mexico in 2017 resulted in 369 fatalities and a Mw7.2 in Haiti in 2021 killed more than 2,200 people.
Although earthquakes cannot be predicted, early warning systems can buy time. They use the faster-moving “P-waves” of a tremor to forecast the intensity of the more damaging “S-waves” which come later, enabling automated systems to cut power supplies, shut down elevators, issue public information, or slow transport. Artificial intelligence is now being used to improve these forecasts. At Stanford University in the U.S., researchers trained the DeepShake early warning system on data from more than 36,000 earthquakes to provide warnings of strong shaking based on the characteristics of an earthquake’s first detected waves.
When a natural catastrophe as unpredictable and destructive as a major earthquake strikes, every second counts.
Seven Lessons from the Turkey-Syria Earthquake
On Feb. 6, 2023, two major earthquakes struck near the border of Turkey and Syria, killing thousands, and affecting an area of 110,000km2 (42,471 square miles). Here are some of the lessons which can be learned from this tragedy:
- Follow seismic codes: It is vital buildings are designed and constructed in compliance with the local seismic design code. Quality of design, materials and workmanship must be prioritized.
- Check soil conditions: Conduct soil investigation studies and select proper foundation systems before the structural design of a building. Ground motion in the Turkey-Syria earthquake was amplified by soft soil and hilly terrain, and some buildings without adequate foundations were damaged because of liquefaction.
- Beware of structural defects: Simple architectural plans such as rectangles or squares fared better than U, L and T shapes or asymmetrical plans. “Soft story” configurations, which have a high ground floor with a large open space, such as a gallery, were more vulnerable, as were buildings where the floor area of upper stories extended beyond that of the ground floor (projections). Other damage was worsened by the “hammering effect” (where there is an insufficient gap between buildings) and poor-quality reinforced concrete.
- Take care with solar panels: With some buildings, the additional seismic loads of solar panels which had not been considered during design stages caused heavy damages when roofs collapsed.
- Secure non-structural elements: Damage was caused in industrial buildings by overturned machinery, equipment, storage, server cabinets, broken sprinkler, and ventilation systems, and fallen suspended ceilings, resulting in material losses and business interruption. Equipment should be anchored, tethered, or mounted using approved anchorage materials and flexible connections.
- Take steps to reduce fire risk: A gas pipeline explosion in Kahramanmaraş highlighted the danger of fires after an earthquake, when pipes, cables, generators, chemical storage tanks, and flammable materials might be displaced. These should all be secured with appropriate seismic bracing or anchoring.
- Include resilient design: Important buildings such as hospitals, schools, and critical industrial buildings should be designed according to “immediate usage” performance levels, which means they are more likely to sustain only limited damage and can remain functional after an earthquake. This can be achieved with elements such as damping systems, which absorb and dissipate earthquake energy to reduce a building’s displacement, and base isolation, which uses flexible bearings between a building and its foundations to reduce the forces transmitted to its structure.
What To Do When an Earthquake Strikes
- When the shaking starts, move away from windows, hanging objects, shelves, cabinets, or large furniture that could be overturned.
- Do not try to walk or run before the shaking has stopped.
- Drop, cover, and hold on! Drop to your hands and knees, crawl under a table or desk, cover your head and neck with one arm and hand, and hold on to the furniture until the shaking stops. Stay on your knees, bent over, to protect vital organs. If you have no shelter, crawl to an interior wall, and use both arms to hold your head and neck.
- When the shaking ends, check whether you have any injuries before helping other people.
- Before you leave the building, turn off your gas and electricity supply to avoid fire.