The Volcano that speaks

Researchers have mapped a complex system of magma channels beneath Oldoinyo Lengai, an active volcano in northern Tanzania. The study, led by Professor Dr Miriam Christina Reiss at Johannes Gutenberg University Mainz (JGU), identifies the physical sources of volcanic tremor faint, continuous ground vibrations caused by the movement of magma and gases.

Research findings

The results, published in Communications Earth & Environment, trace these tremors to two main zones:

· One located about five kilometres below the surface,

· Another close to the volcano’s base.

Data show that these areas behave in synchrony, indicating a directly connected network of magma channels. The system allows magma and gases to circulate beneath the volcano in a pattern similar to fluid flow through connected conduits.

Methodology

Over an 18-month period, the research team deployed seismometers around Oldoinyo Lengai to record continuous ground motion. Analysis of the seismic data in Germany revealed rhythmic vibration patterns linked to magma movement rather than to rock fracturing, which typically causes earthquakes.

Geological significance

Oldoinyo Lengai is the world’s only active carbonatite volcano. Its lava, with a temperature around 550 °C, is significantly cooler and more fluid than the ~1,200 °C magmas found in most volcanoes. Earlier models assumed that such fluid lava would not produce measurable tremors, but the new findings confirm that even low-temperature eruptions can generate complex seismic signals.

Implications

The study provides a clearer understanding of how subsurface magma transport produces continuous tremor and may improve future volcano monitoring and eruption forecasting. By distinguishing normal internal activity from early eruption signals, scientists aim to enhance the accuracy of volcanic hazard assessment in inhabited regions.