| Summary: | Jökulhlaups (also known as GLOF, glacier lake outburst floods) that travel subglacially are only detectable indirectly, via observation of the glacier’s surface deformation (GNSS, InSAR) or the seismic signals they generate.At Iceland’s Vatnajökull glacier, floods from Grímsvötn travel more than 40km below the ice before feeding into the glacial river.To study the propagation and the physics of the jökulhlaups, temporal seismic arrays were installed close to the terminus, i.e. west, southwest and south of Vatnajökull. Frequency-wavenumber-analysis (fk-analysis) and match field processing (MFP) are two seismic methods able to locate the generated tremor along the propagation path. We present insights into Grímsvötn floods between 2014-2016 and October 2022. We discuss the properties of the 3-component seismic data and their location with respect to hydrometric and GNSS observations.Ultimately, these understandings may contribute to improve the early warning of subglacial floods.
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