2019 | Mapping the magmatic systems at Oldoinyo Lengai (Tanzania) with seismic ab-sorption and scattering

Oldoinyo Lengai is the only active volcano on Earth which produces natrocarbonatite lava. It has long been the subject of geological studies; however, geophysical analyses are very sparse while geophysical imaging is unavailable in the area and time-expensive. Seismic absorption and scat-tering mapping (De Siena et al., 2016; 2017) only requires P-wave pickings, origin time and spatial locations of the seismic events to be implemented. As it uses the wider illumination provided by coda waves, it can image magmatic systems with greater depth illumination than standard travel-time tomography. We will use seismic data acquired by the DFG-funded project SEISVOL (Seismic and Infrasound net-works to study the volcano Oldoinyo Lengai) by PI Miriam Christina Reiss to map the structure of the volcano using the code MuRAT (Multi-resolution attenuation tomography analysis) developed by PI Luca De Siena. This will provide a detailed geophysical mapping of the volcano in terms of parameters related to fracturing and magma accumulation (De Siena et al., 2016) constraining the characteristics of the magmatic plumbing system. This collaboration will provide the first image of the subsurface beneath the volcano.

References De Siena, L., Calvet, M., Watson, K.J., Jonkers, A.R.T. & C. Thomas. Seismic scattering and ab-sorption mapping of debris flows, feeding paths, and tectonic units at Mount St. Helens volcano. Earth and Planetary Science Letters, 442 21-31, 2016. De Siena,L., Amoruso, A., Del Pezzo, E., Wakeford, Z., Castellano, M. & L. Crescentini. Space-weighted seismic attenuation mapping of the aseismic source of Campi Flegrei 1983–1984 unrest. Geophysical Research Letters 44, 1740–1748. 2017.