Seismic Precursory Signals before Effusive Eruptions at La Réunion

• Applicant: Professorin Dr. Eva Eibl
• Subject Area: Geophysics
• Term: since 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 440761244

Tracking magma in the ground before volcanic eruptions can help to mitigate the hazards associated with them such as lava flows or ash clouds. From a seismological point of view volcanic eruptions are preceded by precursory signals such as long-lasting seismic ground vibrations called volcanic tremor and earthquakes. These signals can help to understand the complex, interacting processes in the volcanic system better. However, due to sparse station networks on often remote or inaccessible volcanoes and low signal amplitude, these precursory signals are difficult to detect, poorly understood and mainly phenomenologically interpreted. We will study the precursory seismic signals before effusive eruptions at La Réunion Island. The volcano Piton de la Fournaise at La Réunion erupts up to 4 times per year in mostly effusive eruptions within an uninhabited collapse scarp. There is however evidence for explosive volcanism as well as eruptions on its inhabited flanks threatening people and infrastructure on the island. Our approach includes the installation of a cluster of seismometers a so called array and two rotational seismometers in addition to the existing seismic network which is maintained by the Observatory at Piton de la Fournaise (OVPF). These rotational instruments are newly developed and can yield array-like results in combination with a seismometer at a lower infrastructural and personal cost. We study pre-eruptive seismic signals with the aim to (i) improve their location spatially, (ii) track the movement of the source temporally, (iii) improve the understanding of generating mechanisms and (iv) constrain the geometry of horizontal or vertical magma pathways. This will include the testing of the new sensor with respect to the performance of the array and the local network of OVPF in order to in the future (i) simplify the collection of array-like information in harsh environments such as volcanoes or glaciated regions and (ii) mitigate the negative effects of eruptions.

• DFG Programme: Research Grants