An earthquake-triggered rock avalanche on Jan Mayen Island conditioned by Arctic warming

Large earthquakes can trigger cascading environmental impacts in continent (e.g. 1964 Mw 9.2 Alaska and 2015 Mw 7.9 Nepal earthquakes), yet such processes remain poorly documented in oceanic and polar settings. Here, we present a multidisciplinary investigation of the 2025 Mw 6.5 oceanic strike-slip earthquake that occurred on 10 March 2025 along the Jan Mayen oceanic transform fault, Arctic Ocean, and its surface and cryospheric impacts on local Jan Mayen Island. Using relocated local seismicity, regional waveform modelling, GNSS time series, seismic noise interferometry, infrasound observations, high-resolution optical satellite imagery, and long-term air-temperature records, we reconstruct the sequence of events linking the earthquake rupture to a major rock-slope failure. The earthquake, which ruptured for ~40 km long in transform faulting, triggered a rock avalanche from a steep, glacier-adjacent volcanic slope, depositing 0.8-1.2x106 m3 of debris material over ~0.9 km2 of the Kjerulf Glacier and reaching the coastline. Infrasound signals constrain the timing of slope failure to within minutes of the mainshock, supporting a co-seismic trigger. Satellite imagery further reveals contemporaneous calving at the Weyprecht Glacier. We observed from pre-2025 satellite imagery that multiple smaller rock-slope failures between 2019 and 2024, indicating progressive slope weakening prior to the earthquake. Also, long-term air-temperature records show a marked warming trend over recent decades, including the near absence of extreme cold winters since the late 1990s and an increasing frequency of anomalously warm summer days, consistent with Arctic amplification. We interpret the 2025 rock failure at Kjerulf Glacier as an earthquake-triggered collapse of a slope preconditioned by permafrost degradation associated with this warming trend. Our results demonstrate that oceanic strike-slip earthquakes can generate significant onshore geohazards in polar environments and highlight the importance of integrated geophysical and remote-sensing approaches for monitoring earthquake-climate-cryosphere interactions in the Arctic.