Edifice Seismicity, Internal Structure, and Crater Deformation for Constraining Magmatic Processes at Ol Doinyo Lengai Volcano, Tanzania

• Applicant: Professor Dr. Georg Rümpker
• Subject Area: Geophysics
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 563197751

This study will investigate the seismicity, internal structure, and surface deformation of the active Ol Doinyo Lengai volcano in northern Tanzania. The primary goal is to analyze internal processes, such as magmatic fracturing and magma accumulation within the volcanic edifice, and their effects on seismic activity and crater deformation. By employing a range of seismological techniques combined with Global Navigation Satellite System (GNSS)-based deformation measurements, we aim to contribute to a better understanding of the relationships between magma reservoirs, magma transport, magma-induced seismicity, and crater instability. This investigation is motivated by findings from a five-week seismological pilot experiment, which revealed high seismicity within the volcanic edifice. The spatial distribution of seismic events suggests that magma movement induces fracturing and erosion that contribute to the instability of the crater region. To address these processes, we plan to deploy a dense network of seismic stations around the crater and along the flanks of the volcano to characterize the seismic activity and, for the first time, image the internal magmatic structures of the edifice. Repeated GNSS-based field surveys will also be conducted to quantify the deformation of the crater region. By integrating seismological measurements with deformation surveying, we aim to exploit the potential of multiparametric studies for studying active volcanoes. In particular, this study addresses the following research questions: 1. How does the spatiotemporal distribution of seismic activity within the volcanic edifice relate to magma transport and rupture evolution? 2. What insights can seismic imaging provide about the spatial distribution of magma within the volcanic edifice? 3. Can correlations between seismicity, focal mechanisms, and surface deformation provide insights into the stability of the volcanic edifice, specifically of the crater area?

• DFG Programme: Research Grants