Bulge Formation, Water Jetting and Drifting at Strokkur Geyser, Iceland, derived from Video Camera Data

Strokkur geyser in Iceland is located in the Haukadalur valley and features jetting water fountains of hot water every few minutes. In earlier studies we found that Strokkur geyser passes through typical phases: eruption, conduit refilling with water, gas accumulation in a bubble trap and regular bubble collapses at depth in the conduit (Eibl et al. 2021).

In this presentation we focus on the blue bulge that forms at the beginning of an eruption and the following jetting and drifting of the water fountain. We analysed video camera data from 2017, 2020 and 2022 from the ground and from drones to assess the bulge heights and formation speeds. We find that an up to 0.5 m high water bulge forms within 0.7 s at an average speed of 0.6 m/s. Following the bulge burst, we subdivide the eruption phase into a water jet phase and a water drift phase. The water jet reaches a mean height of 16.2 m rising at a maximum average speed of 10.2 m/s. 5 s after maximum jet height is reached the water has drifted to a mean height of 25.6 m at a constant drift speed of 2.0 m/s. We find that eruptions that feature larger bulges also feature larger jet heights and discuss whether there is a link between eruption height and waiting time after eruptions.