Seismic signature of the 23 November 2025 Hayli Gubbi eruption sequence in Afar, Ethiopia

On 23 November 2025, the Hayli Gubbi volcano, located in the Danakil depression of Afar, northern Ethiopia, erupted with an unforeseen massive explosion. The volcano is situated approximately 15 km from Erta Ale, one of the most active volcanic systems in the region. This study provides the first seismic characterization of this event, recorded across a broad regional network including ten permanent seismological stations.

We find that the seismic recordings reveal an eruption sequence consisting of a minute-long precursor phase, a main explosion phase, and secondary events occurring hours later. Two separate wave trains indicate that the main eruption comprised two major explosions with a time delay of several minutes rather than a single distinct event. Accurate event localization is performed through joint inversion of origin time, epicentral coordinates, and wave velocity for independently picked surface wave arrivals from the explosions. Forward modeling strongly supports the assumption of an explosive sequence, as synthetic seismograms match the observed waveforms only when two sequential explosive sources are assumed. Higher-frequency and pulse-like precursor signals were detected within minutes before both main explosions, potentially reflecting early pressurization, conduit processes, or magmatic fracturing preceding failure.

The exceptional magnitude of this event provides valuable insights into the seismic emission of the large explosive eruption, while highlighting the challenges of monitoring active volcanoes in this remote and sparsely instrumented region. The unforeseen nature of the eruption underscores the need for improved local seismic monitoring to better constrain magmatic processes and enable more robust eruption prediction capabilities for volcanoes in Afar.