On Monday afternoon Taiwan was hit by a magnitude 6.2 earthquake. The epicentre of the earthquake was about 57 kilometres off the eastern coast of Hualien. On Taiwan’s 7 tier intensity scale, it reached a 4 in the north east of Taiwan, including in Taipei. At time of writing, there’s been no reports of damage or injuries and no aftershocks recorded, but it provided quite the surprise to many.
According to Taiwan’s central weather bureau, there’s an average of 2,200 earthquakes per year, and approximately 214 of those can be felt. The question is, what affects these numbers and will climate change have any impact?
In 2021, University College London Professor Bill McGuire released a book called ‘Waking the Giant’. In it, he discusses how climate change could be responsible for triggering earthquakes, tsunamis and volcanoes and the devastating effects this could have. In the book, he talks about how past climate events resulted in different natural disasters. For example, whenever the planet emerged from an ice age, the retreat of large ice sheets caused a build up of pressure. This pressure then led to events such as earthquakes and volcanic activity.
The argument he makes is this: If past climate changes increased the frequency of seismic events such as earthquakes, then surely man-made climate changes might have a similar effect. To take one case study as an example, Climate change and global warming is seeing ice Alaska and Siberia thaw for the first time since it formed 11,000 years ago. It’s a topic that still has relatively little research, but it has great significance for climate science and global disaster prevention.
In Taiwan specifically, the relationship between earthquakes and climate change isn’t just limited to the melting of the ice caps. According to a 2021 study from Academia Sinicia, variations in the water cycle might have a role to play in the frequency and intensity of Taiwan’s earthquakes. The study used data from 2002 to 2018 and found that in Western Taiwan, many earthquakes of magnitude 6 or greater happen during Taiwan’s dry season between February and April. In Eastern Taiwan deeper earthquakes were found to be more common in December to February. The paper discusses how when there’s less water stored in the ground because of drought, the Earth’s crust can rebound more easily. This means that even when under low amounts of stress, there can still be earthquakes at higher intensities than would be expected.
Unfortunately for Taiwan, climate change is meaning that droughts are becoming more and more common. Usually, Taiwan relies on its annual typhoon season to provide about half of its annual water needs. An international panel on climate change predicts that because of climate change, the path of the typhoons that usually impact Taiwan will go further north. Whereas on average Taiwan gets around three to four typhoons per year, this may significantly reduce within 10 to 20 years. Already, Taiwan is struggling with drought issues with domestic water use rationed in periods of extreme lack in the summer.
Drought is a big enough issue as it is. Combine that with the idea that droughts could potentially lead to more earthquakes and it’s a recipe for disaster. While most of Taiwan’s earthquakes are completely harmless, danger is never far. Any discussion of earthquakes in Taiwan has to mention the tragic earthquake of September 21st 1999. This earthquake had a magnitude of 7.3 and killed over 2400 people. Taiwan’s learnt a lot since that disaster and buildings are built to be earthquake proof, but it could be walking into more trouble in the future if the science turns out to be true.
Talking about seismic events with any kind of certainty is challenging, if not impossible. This is still a relatively new area of research and the science is still not completely there on whether the link between climate change and earthquakes is a solid one. Let’s just hope for Taiwan’s sake that if the predictions do come true, it’s not too late to prevent the worst of their impact.