Global warming–induced sea level changes could increase earthquake risk
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New research, published in Quaternary Science Reviews, has explored the possibility of the earthquakes being triggered by the global-scale activity of Earth's glacial cycles. Specifically, Man-Jae Kim and Hee-Kwon Lee, of Kangwon National University, South Korea, investigated the possible link to interglacial periods occurring over 100,000 year cycles.
The researchers used electron spin resonance (ESR) dating to age fault gouges, whereby microwave energy is absorbed by unpaired electrons in the magnetic field of particular radioactive elements within the rock as they decay, therefore allowing age determination as the unpaired electrons accumulate.
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One theory is that this may result from stress release due to glacial unloading, as the weight of ice over the landmass reduces with melting. Previous studies have shown that unloading can impact the seismic stress field several hundred kilometers from the ice sheet margin, thus expanding the possibility of intraplate earthquake activity.
However, given that Quaternary (2.58 million years ago to the present) ice sheets may have been too far from the Korean Peninsula to elicit such a response, the researchers instead suggest compressive stress on the underlying lithosphere from glacial meltwater loading causing rising sea levels across the Pacific Ocean may be the answer.
This research has important implications for modern day seismic activity as climate change exacerbates glacier melting and subsequently sea level rise, with the potential to trigger more earthquakes in the future. This will require seismic-prone areas to plan strategies to mitigate against the social, environmental and economic damage caused by earthquake events.