Tourists and geologists visiting an erupting volcano on the Eyjafjallajokull Glacier in Iceland witnessed spectacular sights on Wednesday. The volcano had been dormant for 200 years before this eruption started on 21 March.
According to scientists, the eruption of the volcano is not in itself a threat to local residents, but could provoke an eruption of the nearby larger and more dangerous Katla volcano.
Icelandic authorities have evacuated 450 people from the surroundings of these two volcanos.
Authorities initially feared the eruption which occurred below the 100-square-mile (160 square-kilometre) Eyjafjallajokull glacier could have triggered floods if the glacial ice melted.
But after an aerial survey on Sunday they concluded that it struck near the glacier in an area where there was no ice.
Iceland sits on a large volcanic hot spot in the Atlantic's mid-oceanic ridge.
Volcanic eruptions, common throughout Iceland's history, are often triggered by seismic activity when the Earth's plates move and when magma from deep underground pushes its way to the surface.
Scientists in Iceland have been monitoring the recent activity using seismometers and global positioning instruments.
Like earthquakes, however, it is difficult to predict the exact timing of eruptions.
The population around the Eyjafjallajokull volcano and the glacier that bears the same name is sparse - unlike the area around the Katla volcano, which is also covered by glacial ice and poses a greater danger of floods.
There hasn't been an eruption near the Eyjafjallajokull glacier since 1821.