Poás continues to emit tall gas plumes from its hot spot

After years of relative calm, the dome of the Volcán Poás crater is registering high temperatures and emitting gas plumes that may go a kilometer in the air.

That’s the report from the Observatorio Vulcanológico y Sismológico de Costa Rica. The agency, which is affiliated with Universidad Nacional in Heredia, said that staffers observed that the dome, a lump of volcanic material on the edge of the crater, was incandescent.

This is similar to what has been observed in 1981. The glow is caused by the high temperatures under the materials. For 30 years until 2008 the temperature of the gas vents in the dome has been around 93 degrees C., about 200 degrees F.

Lately the temperature has soared to more than 850 C., about 1560 F. Researchers don’t really know because the high temperature broke the device they were using to measure the heat.
The vents in the dome are liberating quantities of sulfur dioxide, hydrogen sulfide, hydrogen chloride and also vast amounts of water vapor, they said.

Staffers went into the crater near the dome Aug. 9 and noticed that gas emissions below are agitating the highly acidic lake in the crater. However, in the four hours they were there, there was no eruptions, they reported. The lake continues to be about 51 degrees C., about 124 F. Staffer María Martínez did manage to capture a kilometer-high plume of gas jetting from the dome last May 18.

The researchers also used a thermal imaging camera to photograph the hot spots in the dome. The camera is able to cut through the haze and clouds that usually are found in the crater.

The crater and dome have not yet reached the temperatures registered in 1981 to 1983. The dome is easily viewed from the visitor’s observation area.

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