Landsvirkjun

Ear-splitting noise from borehole 36 in Krafla

13. December 2007

According to experts at Iceland GeoSurvey (ISOR), the hole vented powerfully, with relatively pure steam. No water accompanied the steam, and this was the case the whole time. After approximately 5 to 10 minutes, the steam started to darken, and for a while, the cloud was almost black, similar to what one sees in volcanic eruptions. There was a strong southerly wind during the venting of the hole, and the snow under the cloud, which extended for a couple of hundred metres, was blackened. The deposit was extremely thin but dense, hardly thicker than 1 to 2 millimetres. Approximately one hour later, the steam plume emitted from the muffler had become quite clean. It is considered likely that hydrogen sulphide caused these changes in colour.

No precise energy figures were obtained, as measuring instruments were damaged in all the fuss, but according to ISOR experts, it is probable that the energy was between 20 and 30 MW after the venting.

The borehole is on the KJ-34 bore-plan and was directionally drilled to the north-west. The bottom of the hole is approximately 1 km, horizontally, from the opening of the hole. The final workday of the driller Jötunn on the hole was 19 November when it was completed.

The picture below shows Kristján Stefánsson who, together with Karl Emil Stefánsson, both employees at Krafla, was responsible for the venting of the borehole. The lower picture shows how dense the steam cloud emitting from the muffler was.

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