The following was received by the Smithsonian's Global Volcanism Network. This report is preliminary and subject to change as the event is studied in more detail. We will forward additional significant information as it becomes available.
Wednesday, 2nd October 1996 09:30
Last Sunday, 30th Sept there started a series of earthquakes in Brdarbunga, in Vatnajokull. This event continued on Monday, and at 22:30 it was evident that a volcanic eruption had started below the glacier. The eruption site is east of Bardarbunga.
In Thuesday 1. Okt, observation indicated that a 5-6 km long row of cauldrons was growing through the day, being roughly 100 m deep, and 2 km wide. The eruption site is between Bardarbunga and Grimsvotn, and is a fissure eruption. The glacier is 600 m thick over the eruption site and the cauldrons indicate a flow of water to the Grimsvotn caldera to SE. In the Grimswotn caldera is a lake that periodically surges to south, under Skaftarjokull forming "jokulhlaup". It was estimated that the eruption had filled 25% of the volume of the caldera and a surge is evident if the eruption continues. Weather was fine throughout the day.
Today 2nd Okt is SE rain and storm, visiblitiy low and observation from air difficult. From seismometers it is evident that the eruption continues and in 09 news it was reported that the eruption had broken through the glacier and the eruption column is in the order of 5 km. It is not possible to forcast the length of the eruption, several small eruptions have occurred in this area but also some of the largest in Iceland are from this fissure system.
Wednesday, 2nd October 1996, 10:00
Eruption below Vatnajokull glacier is more concentrated in one place as is usual in such eruptions.
Flight observation before 09 this morning confirmed the ash-column to reach several km. This eruption is at the same site as in 1938. The thickness of the glacier is thinner at this place as the 1938 eruption did build a subglacial ridge. The glacier is around 450 m thick where the eruption did erupt through the glacier. The 1938 eruption is expected to have lasted about 1 week, perhaps longer as it was only observed when it had melted throug the glacier.
Water continues to flow to Grimsvotn caldera at a rate about 5000 m3/sek. A surge in Skeidara river is expected to begin tomorrow, after evt. 24 hrs if this inflow rate continues.
Ash is travelling N and NE at the speed of 70 km/h and in the next few hours it is supposed to fall in N and E Iceland. All flight is cancelled in N and E Iceland at the moment.
Wednesday, 2nd October 1996, 12:00
Eruption column is 15000 feet, and now the eruption fissure is 10 km long and has extended through the glacier at 2 sites, the second site is 10 km to the north of the opening that opened at 05 this morning. Ash has started to fall in N Iceland Hazardzone is now Vatnajokull, Axarfjordur to Hunafloi in N Iceland and as a low pressure is going over Iceland, ash can fall anywhere the next 24 hours.
Helgi Torfason heto@os.is