Sinkholes observed at Vesturbunki, Surtsey

Researchers have identified and monitored sinkholes and fissures along the outer margin of Vesturbunki, one of Surtsey’s tuff cones, revealing a dynamic subsurface process. These features, first observed in 2015, were traced over nearly 500 meters and showed variability in their presence across multiple field visits (2017, 2019, 2025). The study suggests that these sinkholes are likely driven by a combination of island-wide subsidence, local compaction of volcanogenic material, and possibly triggered by seismicity. Surface temperature monitoring between 2008 and 2025 indicated Vesturbunki is consistently hotter (up to 100°C) compared to Austurbunki (up to 96°C), with fluctuations linked to subsurface heat flow. Seismic data from 2009–2024 showed low to moderate activity, though hypocenter locations remain uncertain due to sparse station coverage. The findings underscore the need for continued monitoring and installation of a local seismic station on Surtsey to better understand these processes.

Ásbjörnsdóttir, L., Jónasson, K., & Guðmundsdóttir, M. (2025). Sinkholes observed at Vesturbunki, Surtsey. Surtsey Research, 16(1), 93–98. https://doi.org/10.33112/surtsey.16.9