Measured in the Alps: Climate change causes more earthquakes
Global warming is causing various natural disasters to become more frequent or more severe. Earthquakes are now being added to the growing list.
The Grandes Jorasses mountain is part of the Mont Blanc massif.
(Image: Michael Bacher, CC BY-SA 3.0)
Global warming increases the risk of destructive earthquakes occurring in mountains. This has been determined by a research team from Switzerland and France, using a mountain in the Mont Blanc massif in the Alps as an example. Precise seismic measurements showed that a heatwave in 2015 on the border between France and Italy triggered numerous smaller earthquakes under the Grandes Jorasses. Even if these were not dangerous themselves, the probability of stronger tremors increases with the number of such weak quakes. “This dramatically increases the danger,” explains co-author Toni Kraft from ETH Zurich to the scientific journal Science.
Melt water causes earthquakes
The basic explanation for the observation is not new, the team explains, but the extent is. It has been known for decades that water underground under the high pressure of the rock masses above plays a central role in the formation of earthquakes. It is also known that there is a clear correlation between seismic activity in the Mont Blanc massif and the seasons – with more quakes in late summer when meltwater penetrates the rocks. For the analysis now presented, the data from a precise seismometer installed 13 kilometers from the mountain was examined, which has registered more than 12,000 earthquakes that were previously overlooked.
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The data showed a significant increase in the strength and frequency of earthquakes after 2015, when a severe heatwave caused a lot of ice in the high mountains to melt, summarizes study leader Venera Simon. Based on weather data, her team then confirmed that strong heatwaves also resulted in such increased seismic activity elsewhere – but with a delay of one year for shallow earthquakes and two years for those at depths of up to seven kilometers. Together with other studies, an “impressively clear picture” emerges. In the Alps, the quakes do not pose a concrete threat, but in other mountain ranges the consequences could be more dramatic.
The fact that global warming is causing very different natural disasters to become more severe and more frequent is nothing new. Most of these are droughts, heatwaves, or storms. However, four years ago, a research team from the UK explained that less obvious events are also affected. It determined that man-made global warming could even cause more volcanoes to erupt, which in turn would further drive climate change. The link to earthquakes may also come as a surprise to some. The study is now being presented in the journal Earth and Planetary Science Letters.
(mho)
