Science reports:

Climate change is worsening many natural hazards, including droughts, heat waves, and storm surges. Now, a new one has joined the list: earthquakes. Researchers have found that as global warming accelerates melting of mountaintop glaciers, the meltwater, percolating underground, increases the risk of damaging earthquakes.

The evidence comes from beneath Grandes Jorasses, a glacier-clad peak in the Alps that is part of the Mont Blanc massif, home to Western Europe’s tallest mountains. Precise seismic records show a heat wave in 2015 kicked off a surge of small earthquakes under the mountain. Although the tremors themselves were not damaging, the chances of large earthquakes are known to rise with the frequency of small ones. “It increases the hazard dramatically,” says Toni Kraft, a seismologist at ETH Zürich and co-author of the new study, published this month in Earth and Planetary Science Letters.

Scientists have known for decades that water, pressurized by the weight of kilometers of rock overhead, plays a key role in triggering earthquakes. When water percolates into the pore spaces of rocks, the added pressure can counteract forces that keep faults clamped shut, leading to slip. In eastern Taiwan, for example, movement along a fault—one that ruptured in a magnitude 6.8 earthquake in 2003—is thought to vary seasonally with rainfall. The same mechanism is at play in the clusters of earthquakes sometimes triggered by natural gas fracking, wastewater storage, and advanced geothermal energy projects, which all inject pressurized water deep underground. [Continue reading…]