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SEISVOL

 is short for Seismic and Infrasound netwroks to study the volcano Oldoinyo Lengai. This research is funded by the DFG (German Research Council) for the duration of three years.

Oldoinyo Lengai in the North Tanzanian Divergence (NTD) is the only active natrocarbonatite volcano world-wide and presents an important endmember magmatic system in a young rift segment of the East African Rift System (EARS). This volcano typically experiences long-duration episodes of natrocarbonatitic effusions with intermittent short-duration explosive eruptions. These changes may be driven by stress interactions between different magma networks beneath Oldoinyo Lengai and neighboring rift volcanoes or caused by a complex differentiation process in which, driven by CO2, natrocarbonatitic magma is exsolved from one magma chamber. To better understand the role of the stress interactions and magma plumbing on the eruptions dynamics, this study aims to constrain the subsurface magmatic architecture of Oldoinyo Lengai, and a zone of ongoing seismicity and intrusive activity below the extinct 1 Ma-old Gelai shield volcano and active Naibor Soito monogenetic cone field.

We collaborate with Dr. Emmanuel Kazimoto, a researcher from the University of Dar es Salaam, as well as his student Amani Laizer, BSc. We are indebted to them as well as the Tanzania Commission for Science and Technology (COSTECH) and the local Massai community.

 

Network

In February/March 2019, we installed a dense seismic network and infrasound sensors closely situated around the active Oldoinyo Lengai edifice. This network will significantly reduce the detection threshold of volcano-tectonic events, allowing us to observe temporal changes in the magmatic system and provide detailed imaging of the globally-unique Oldoinyo Lengai plumbing system. An array of 10 seismic stations will allow us locate possibly weak signal from the volcano and locate earthquake beyond the dimensions of the network.

All instruments will remain in the field for ~1 year and serviced regularly.

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First Results

At EGU 2020, I presented preliminary results of the seismicity and structure beneath Oldoinyo Lengai and adjacent Gelai shield volcano of the first 10 months of data. We located over 7000 earthquakes between the 1st of March and 31st of December 2019. Due to the covid-19 pandemic, the conference took place virtually. Please check out my presentation for details.

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Field work pictures