Research press release


Nature Communications

Geoscience: A land of ice and fire


今回、Benjamin Edwardsたちは、カムチャツカ半島での火山噴火を目撃し、雪原の上下と、雪原の亀裂の中を進む溶岩流の様子を観測した。Edwardsたちは、前進する溶岩流の手前に観測孔を設置して、雪原での溶岩の流れ方、そして溶岩と雪塊の界面での融解の程度を明らかにした。その結果、角ばったアア溶岩が雪原上を進み、融解水が溶岩流下に蓄積したのに対して、滑らかに流れるパホイホイ溶岩は、雪原下と亀裂の中を流れたため、融解水と溶岩の相互作用が起こり、独特な溶岩組織が形成された。


Quantitative observations of an eruption in far-eastern Russia show that two different kinds of lava, 'a'a and pahoehoe, interact with the snow cover in very different ways, reports a study published this week in Nature Communications. Understanding how volcanoes in cold regions interact with snow and ice is vital for hazard mitigation and flood damage prevention.

Benjamin Edwards and colleagues witnessed an eruption on the Kamchatka Peninsula and observed lavas moving on top of, beneath and through fractures in the snow. They were able to dig observation pits in front of the advancing lava flows to identify how lava moved through the snow and how much melting was happening at the lava-snow interface. They found that blocky 'a'a lavas advanced on top of the snowpack with melt water accumulating beneath the lava flow, whereas smooth flowing pahoehoe lavas advanced under or inside the snowpack, allowing melt water to interact with the lava and producing distinctive lava textures.

Although the observed volcano is remote, these findings could be important for investigating the possible hazards of ice-clad volcanoes in more populated areas; glacial floods have been identified as the most frequently occurring volcanic-related hazard in Iceland. The authors also suggest that their findings will help to identify ancient lava-ice interactions on Earth, where retreating snow-lines may indicate periods of climate warming, and on Mars, where regions of volcano-fluid interaction may have harboured life.

doi: 10.1038/ncomms6666

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