The science of Haida Gwaii: How quake-damaged hot springs are trickling back to life


Hope isn't lost for Haida Gwaii's hot springs, it seems, as Parks Canada staff have reported that hot water is once again seeping from the rocks near two of the hot spring pools.

"The pools themselves remain dry, although we did find some hot water flowing out of a crevice at the base of a cliff in front of one of the pools, so that's very encouraging for us." said Ernie Gladstone, the superintendent of the Gwaii Haanas National Park Reserve and Haida Heritage Site, according to CBC News.

"We're hoping that the water levels continue to rise on site."

[ Related: Hot water flowing again on Haida Gwaii's Hotspring Island ]

Haida Gwaii took a hard hit late last October, when a 7.7 magnitude quake shook the island. Thankfully there were no serious injuries and little in the way of damage, but the quake did take away one of the island's precious natural resources — its famed hot springs.

Hot springs typically form along seismic fault lines, like the Queen Charlotte fault that runs right through the Haida Gwaii islands, or above volcanic hot-spots like Yellowstone National Park.

The water that feeds these springs is usually from deep underground. Water trickling down through layers of rock is turned to steam by geothermal heating — either by direct contact with lava, rocks heated by friction, or (if the water goes deep enough) the Earth's mantle itself — and the steam is forced upward towards lower pressures. This steam is continuously pushed upward by more steam produced below, it eventually cools back into water as it nears the surface, and it emerges into the spring.

For Haida Gwaii, the spring water is heated by a warm reservoir above the fault line. The springs most likely dried up because the earthquake shifted the rock layers over this warm reservoir, therefore changing the routes that water used through the layers. This either prevented the water from reaching the reservoir or it diverted the rising steam elsewhere.

There are a few possibilities for why the hot water has started to flow again.

It could simply be a case of the 'tenaciousness' of the whole system that feeds the springs, so the water either found another way down to the reservoir by some new path, or the rising steam found a way around or through the layers to reach the surface again.

It's also possible, though, that the magnitude 7.5 earthquake that struck to the north of the region earlier this month shifted the layers of rock again, either reopening the same pathways the water used before, or creating new ones for the water to use to either reach the heat reservoir or back to the surface (or both).

[ Related: Strong quake shakes West Coast, reignites fears of the 'big one' ]

Either way, only time will tell if the springs will be back to normal someday, but this is certainly encouraging news.