What do fans of Taylor Swift and tectonic plates have in common? Both can cause earthquakes. The ground will probably shake more often in the future, according to a recent study. There is a specific reason for this, explains study author Marco Bohnhoff.
Mr Bohnhoff, that climate change earthquake sounds very far-fetched. How did you come up with this idea?
We know from previous studies of water level fluctuations in reservoirs or from oil and gas production, where water is forced into the ground, that small changes in pressure can trigger earthquakes. Whether the global rise in sea level could have an influence on the occurrence of earthquakes has not yet been discussed.
To person
Marco Bohnhoff works at the German Research Centre for Geosciences at the Helmholtz Institute in Potsdam. There he is investigating whether humans can trigger earthquakes by interfering with the ground. His recent study on the topic appeared at the end of May. With the star he talked about the results.
They investigated this in a recent study.
We have developed a model that incorporates the IPCC’s predictions of sea level rise. Our scenarios show that even small fluctuations in sea level change the pressure on the ground in such a way that earthquakes become more likely.
How high would the water have to rise?
One meter is enough to trigger earthquakes, in some places even less.
Which earthquake was most recently caused by climate change?
This cannot yet be measured clearly. Historically, however, climate change has repeatedly triggered tremors, for example in Scandinavia. Earthquakes have occurred there in the past 10,000 years since the last ice age, although there is no active plate boundary there like around the Pacific. We do know, however, that Scandinavia is still rising today due to the melting of the ice sheets. The tension in the ground can be calculated and so the earthquakes in the region can be attributed to the relief caused by the melting ice. Our model now shows that the probability of earthquakes is increasing due to man-made climate change.
Earthquakes are likely to be less common in Northern Europe, but they cannot be ruled out anywhere
Which regions of the world are affected?
When sea levels rise, the risk initially increases wherever there is water. This applies to around 70 percent of the earth’s surface. Coastal regions, where 40 percent of the world’s population lives, are particularly at risk. The situation is particularly critical in seismic risk areas such as San Francisco, Los Angeles or Istanbul. There, even minimal changes in sea level could trigger strong tremors.
Sensitive structure: An overview of the tectonic plates on Earth
© Depositphotos / Imago Images
Are they more severe there than elsewhere?
In certain regions, yes, for example along the Pacific Belt of Fire, on the west coast of Latin America, off Japan or in the Mediterranean. In these subduction zones, the continental plates meet and slide over each other. If the pressure increases there due to rising sea levels, the plates initially stick together. Earthquakes are delayed somewhat there, but then become even stronger because the loading process continues unabated.
Dangerous zone: Several tectonic plates collide at the Ring of Fire around the Parifik
© Depositphotos / Imago Images
What are your predictions for Europe?
To put it simply, the south of the continent is particularly affected – Greece, Italy and Turkey. Earthquakes are less likely to occur in northern Europe, but the examples of Scandinavia and India show that they cannot be ruled out anywhere. It will also affect regions that we do not yet expect. In 2001, for example, there was an earthquake measuring eight on the Richter scale in the state of Gujarat in India. At that time, no one knew that there was a seismic risk in the northwest of the country on the border with Pakistan, because earthquakes there only occur every 700 to 800 years.
Loud United States Geological Survey There are already over a hundred thousand earthquakes worldwide each year, more than 100 of which have a magnitude of six or more. How much will the number increase?
We haven’t calculated that yet, but we want to continue researching this area.
Are accurate earthquake forecasts even possible?
We still need to map the connection between rising sea levels and earthquakes more precisely. In theory, we would need to carry out measurements for at least 100 years to do this, because the actual object – the entire Earth and long-term climate changes – cannot be captured in a few years. But we don’t have that much time, so we are specifically selecting regions where the effects of rising sea levels on ground pressure can be measured. At the same time, we are carrying out measurements in geological reservoirs and at dams and testing simulations. This allows us to create models that can be transferred to different regions, because the physical effects of rising sea levels are the same everywhere.
It is not the earthquakes that are the problem, but the vulnerable infrastructure
Can such natural disasters still be prevented?
That is unlikely. Even if we were to stop our CO2 emissions today, sea levels would continue to rise. Only when this process ends will earthquakes become less frequent again. But that could take centuries, if not millennia.
What does this mean for the people in the risk areas? Will they have to leave their homes?
“Earthquakes don’t kill people, but buildings do,” we scientists say. It’s not the earthquakes that are the problem, but the vulnerable infrastructure. The only reason there were so many victims in the earthquake disaster in southeastern Turkey in February 2023 was because the buildings were unstable. The best protection is to build earthquake-proof.
San Francisco, Lisbon, Tangshan
Some destroyed entire cities: the most devastating earthquakes in history
Are there any earthquake-proof cities?
A prime example of this is the Tokyo-Yokohama metropolitan area, one of the largest megacities. The government has invested heavily there over decades, and building regulations are very strict and are also adhered to. The earthquake in 2011 was one of the four strongest earthquakes ever recorded worldwide, but the seismic waves destroyed relatively few buildings or claimed human lives. The greatest damage was caused by the tsunami. In the Taiwanese capital Taipei, which is also at risk of earthquakes, there is a 400-meter-high building with a counterweight designed to compensate for fluctuations. The building has not yet experienced a major earthquake, but it should be able to withstand strong tremors.
Do you have any tips for cities like Rome, Athens or Istanbul in southern Europe if the ground there shakes more often in the future?
We have to adapt our building regulations and, above all, comply with them. There is no way around it. It is technically possible, but in some cases it is also expensive.