Tuesday marks one month since a record wave of seismic activity started at and around the volcano of Bardarbunga. At least 20,000 earthquakes struck the area in that period, according to estimates from the Icelandic Met Office.

186 earthquakes of magnitude 3.0-3.9 were detected. 43 quakes were of magnitude 4.0-4.9, most of them at Bardarbunga’s caldera. A total of 23 earthquakes were detected of magnitude 5.0 or greater, all at Bardarbunga. The largest earthquake, a magnitude 5.7, struck on 26 August. That’s the largest earthquake in Iceland since a M6.3 struck east of Reykjavík in 2008.

No significant changes have been observed in the ongoing lava eruption at the lava field of Holuhraun, north of Bardarbunga volcano. Sulfur dioxide pollution from the eruption continues to plague people in the northern and eastern parts of Iceland, though it causes no immediate harm to people.

A M5.2 earthquake struck Bardarbunga Tuesday afternoon. The subglacial volcano’s caldera continues to subside at a rate of 50 cm (20 inches) a day, according to scientists.

Three scenarios of future development are still considered most likely. Firstly, that the subsidence of Bardarbunga’s caldera will stop and the Holuhraun eruption slowly fades out.

Secondly, the subsidence could continue, along with the eruption in Holuhraun. Another eruption could start, possibly under glacier. In this scenario, the eruption(s) could last for a longer time, with lava volume possibly measured in cubic kilometres. Should a subglacial eruption occur, explosive action and glacial floods should be expected.