Volcano erupting basaltic lava (18 May 2021) (Geldingadalur Valley, Iceland) 9 : 無料・フリー素材/写真
Volcano erupting basaltic lava (18 May 2021) (Geldingadalur Valley, Iceland) 9 / James St. John
| ライセンス | クリエイティブ・コモンズ 表示 2.1 |
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| 説明 | (Web camera screen capture video clip taken on 18 May 2021)----------------------------------------------------------Iceland is a volcanic island in the North Atlantic Ocean between Britain and Greenland. It is situated on the Mid-Atlantic Ridge, along which the North American Plate and the Eurasian Plate separate and new oceanic crust forms. Seismicity in the area is due to subsurface magma movement from hotspot (mantle plume) activity, as well as seafloor spreading (= tectonic divergence). Magma reaching the surface results in volcanic eruptions. Some famous eruptions in Iceland include Laki (1783), Surtsey (1963-1967), Eldfell (1973), Hekla (1991, 2000), Eyjafjallajökull (2010), and Grimsvötn (2011).On 19 March 2021, a basaltic lava flow eruption started in the Geldingadalur Valley, next to the Fagradalsfjall Volcano in southwestern Iceland's Reykjanes Peninsula. This followed a swarm of about 50,000 earthquakes that occurred during the previous month. The eruption reportedly started as a fissure eruption - lava was spewed from an extensive crack in the ground. This evolved into a short chain of spatter cones, one of which ended up being larger than the others (= main cone). Subsequent activity resulted in a second sizable spatter cone that developed next to the main cone. Eruptive activity continued into April 2021. Both "original" spatter cones had ceased activity by late April 2021.On 5 April 2021, a new fissure eruption started nearby, close to Merardalir Valley (see: www.flickr.com/photos/jsjgeology/51104474410 ). The fissure eruption rapidly evolved into a line of small spatter cones. On 13 April 2021, additional small spatter cones emerged between the Geldingadalur Valley examples and the near-Merardalir Valley examples.The active cone seen here has grown from one of the ~mid-April 2021 structures. Overnight, in the early morning of 2 May 2021, this cone started having pauses and restarts. Pause durations increased as the morning hours progressed. Restarts involved impressively high lava fountaining. This behavior continued over the following weeks. In the early morning of 7 May 2021, tall lava fountaining occurred with a ~7.5 to 12 minute periodicity. In the late evening of 17 May and early morning of 18 May, fountaining occurred every 7 to 8 minutes.Note: the web camera has been out of focus for the previous 1.5 weeks. The rim of this cone has grown considerably in height since 7 May 2021. |
| 撮影日 | 2021-05-17 19:45:51 |
| 撮影者 | James St. John |
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