冰岛火山的火山灰与闪电
影像来源与版权:Sigurður Stefnisson

说明:为什么这个冰岛火山爆发,会产生这么多的火山灰呢?虽然这道火山灰流的火山灰含量并非空前,不过因为它飘过人口稠密地区而备受关注。冰岛南部的埃亚菲亚德拉冰盖(Eyjafjallajökull)火山,从2010年3月20日开始爆发,第二次喷发出现在4月14日,而且喷口位在一个小冰川的下方。这两次的爆发规模都不大,但第二次的喷发融化了大量的川冰,使熔岩冷却碎裂成砂粒大小的玻璃碎片,并随火山烟尘扶摇直上。在这张第二次喷发时拍摄的影像里,闪电照亮了从埃亚菲亚德拉冰盖火山喷出的火山灰。
翻译:“每日一天文图”成大物理分站

Ash and Lightning above an Icelandic Volcano
Image Credit & Copyright: Sigurður Stefnisson

Explanation: Why did a picturesque volcanic eruption in Iceland create so much ash? Although the large ash plume was not unparalleled in its abundance, its location was particularly noticeable because it drifted across such well-populated areas. The Eyjafjallajökull volcano in southern Iceland began erupting on 2010 March 20, with a second eruption starting under the center of a small glacier on 2010 April 14. Neither eruption was unusually powerful. The second eruption, however, melted a large amount of glacial ice which then cooled and fragmented lava into gritty glass particles that were carried up with the rising volcanic plume. Pictured here during the second eruption, lightning bolts illuminate ash pouring out of the Eyjafjallajökull volcano.
Astronomy Picture of the Day 05/12/2019