Tracking changes in magma transport from very-long-period seismic signals at Piton de la Fournaise volcano

Changes in magma properties and transport geometry can have a direct impact on volcanic activity. However, such variations can be difficult to track during eruptions. We report previously undetected very long-period (VLP) signals at Piton de la Fournaise that can be used to probe changes in magma transport. Source analysis of VLP events during the August-October 2015 eruption indicates a source depth of about 0.9-1.2 km and points to the resonance of the magma dike feeding the eruption. The evolution of the resonance period reveals a shortening of the dike when the magma flux decreases at the end of the eruption. VLP events are actually quite frequent at Piton de la Fournaise: all eruptions analyzed in this study exhibit VLP signals that are indicative of rapid drops in lava discharge. This work encourages the detection of VLP signals to monitor changes in magma flow during volcanic eruptions, and anticipate the corresponding evolution in effusive activity.& COPY; 2023 Elsevier B.V. All rights reserved.

Automated summary

Changes in magma properties and transport geometry can directly impact volcanic activity, but tracking these variations during eruptions can be challenging. This study reports previously undetected very long-period (VLP) signals at Piton de la Fournaise volcano that can be used to monitor changes in magma transport. The analysis shows that VLP events during the 2015 eruption indicate a source depth of 0.9-1.2 km and point to the resonance of the magma dike feeding the eruption.