Erta Ale volcano (Ethiopia): satellite image shows flank eruption site

A new Landsat 8 satellite image from yesterday published by Nasa's Earth Observatory site shows the location of the new flank eruption at Erta Ale.
It seems that there are two fissure eruption sites on the flanks of the volcano, at distances of approx. 3 and 4 km SE from the lava lake in the summit caldera.

Additional details about the flank eruption:
(based on a post from Culture Volcan)
According to eyewitness reports, it started on 21 Jan around 17:00 local time, when lava flows became visible covering a large area in the southern part of the caldera, at 2 km distance from the lava lake.
A close analysis of the satellite image shows that at least 3 vents opened southeast from the summit, along the NW-SE trending axis of the shield volcano between 2-4 km distance from the lava lake.

Before and during the opening of the flank fissures, large-scale collapses occurred in the summit area, involving both the northern and southern (lava lake containing) pit craters, and generating significant ash plumes that were visible from base camp.
The upmost new vent was located approx. 100 m lower in elevation than the lava lake while the lowest was at apprx. 400 m elevation, i.e. approx. 250 m lower. The eruptive fissures did apparently not produce large fountains, but generated three distinct lava fields:
- one to the northeast, reaching about 3 km length,
- a smaller one to the west (about 1 km), and
- one to the SSE, reaching about 2 km in length.
The surface occupied by the first two (on either side on the northermost fissures) can be estimated to be about 1.5km² (1,500,000m²), while the southern flow is about 0.35 km² (350,000 m²) large.

As a result of the sudden draining of the magma, the lava lake in the summit pit crater was reported to have dropped by 80-100 m and was affected by large rim collapses, making an approach extremely dangerous. The situation is similar for the northern pit crater.

For the time being, it is unclear whether the flank eruption was caused by simple hydraulic pressure of the high-standing magma column itself, forcing the opening of a fracture at lower elevation and draining the overlying magma column, or by a true rifting episode, i.e. a significant influx of magma from depth pushing its way into a lateral dike, or a combination of both.