Is global warming causing small earthquakes in the Alps?

Among the least awaited effects of climate change, there seems to be also to make the mountains tremble. According to a study carried out in the heart of Mont Blanc, global warming it could generate small earthquakes in the Alps.

The melting water of the glaciers that melt at an increasingly sustained rhythms infiltrates the rocks and comes to exercise pressure on faultsincreasing the risk of SISMI. For the first time, convincing evidence of this bond were found, recently observed in the Colorado mountains and probably also present in highly seismic areas such as the Himalaya chain.

For some time we have been knowing that perception, the slow passage of water in the small pores of the rock under the effect of the force of gravity, is linked to the trial of earthquakes. The pressure exerted by the liquid can interfere with the balances of strength on the faults and cause their sliding. Small earthquakes can be triggered by the seasonal variations of rainfall (such as monsoons), by the works of deep geothermalia that inject water into the subsoil, from fracking (the injection of fluids to fracture the rock and extract from the subsoil fossils).

Global warming also mobilizes large quantities of water through the fusion of glaciers. Alpine they have lost about 30% of their surface in the last 30 yearsbut never before this ice transformed into the water had been connected to earthquakes.

Toni Kraft and Verena Simon, Sismologists of Hut of Zurich, observed that in the Mont Blanc region, the small tremors recorded by the seismometers they tend to increase in summerin the period of Massimo Disgeel, and to decrease again at the beginning of the following spring.

When they analyzed the data on thousands of small and negligible earthquakes captured by a seismometer installed in 2006 about 13 km south of the Grandes Jorasses, a group of peaks in the northern part of the Mont Blanc massif, they realized that their magnitude and frequency had increased from 2015, after a strong wave of heat.

By studying the meteorological data of the area, scientists noticed that the most intense heat waves seemed to raise the seismic risk in an important way: and since the entry of the water in the rock takes time, between great heat and earthquakes there was a “delay”, one year for superficial seismes and two for those up to 7 km deep.

The phenomenon could be widespread globally It is more accentuated in the areas characterized by an even more widespread presence of glaciers, such as the Himalayas.

It will be necessary to take this into account in the seismic risk assessments for mountain communities.