Along New Zealand fault, precipitation contributes to plates’ slip and slide
Where it rains, it rumbles. Rainwater and snowmelt help fuel intense earthquakes along a New Zealand tectonic fault, new research suggests.
Tracing the source of water flowing through New Zealand’s Alpine Fault shows that more than 99 percent of it originated from precipitation, researchers report April 19 in Earth and Planetary Science Letters. Scientists knew that underground fluids help trigger quakes, but the origins of these fluids have been uncertain. In this case, the nearby Southern Alps concentrate rainfall and meltwater on top of the Alpine Fault while the fault itself serves as an impermeable dam that traps the water.
The fault “essentially [is] promoting its own large fluid pressures that can lead to earthquakes,” says study coauthor Catriona Menzies, a geologist at the University of Southampton in England. Identifying the fluid source will help