Extensive Micro-Earthquake Activity Observed After Cumbre Vieja Eruption

A comprehensive analysis of over 17,000 microearthquakes has provided critical insights into the Cumbre Vieja volcano on La Palma, following its eruption. This extensive research sheds light on the intricate dynamics of volcanic activity and the geological processes that occur beneath the surface.

Significant Findings from Seismic Studies

The recent publication in Geophysical Research Letters details a study conducted by the Italian National Institute of Geophysics and Volcanology (INGV) in collaboration with the Canary Islands Volcanology Institute (Involcan). This research focuses on the internal structures of the volcano, which became active on September 19, 2021, marking a significant geological event that attracted the attention of scientists worldwide.

Luca D’Auria, the Director of Volcanic Monitoring at Involcan, remarked on the unique opportunity to study a newly formed volcano while its internal structures remain active and incandescent. The research utilized advanced seismic tomography techniques to analyze the earthquakes recorded during the eruption, enabling the creation of a three-dimensional representation of the first 1,500 meters beneath the volcano. This innovative approach allows researchers to visualize the subsurface features of the volcano in unprecedented detail.

This analysis was made possible by data collected from a network of 17 temporary seismic stations that were established around the volcano shortly after the eruption. These stations captured thousands of microseisms over a span of nine months, which were generated by the cooling magma’s thermal contraction and the movement of gases. The data collected is invaluable for understanding the ongoing geological processes and the potential for future eruptions.

Understanding Volcano Dynamics Through Seismic Data

The researchers highlighted the role of artificial intelligence in processing the seismic data, which allowed them to effectively differentiate between useful seismic waves among the recorded microseisms. This advanced analysis facilitated a deeper understanding of the velocity patterns of seismic waves and their interrelations, providing insights into the physical properties of the volcanic materials.

Such measurements are crucial as they serve as indicators of both temperature and the presence of fluids within the volcano. The findings revealed that the surface layers exhibited a low ratio, indicating that the rocks are porous and saturated with gas or steam. In contrast, deeper layers showed an increased value, suggesting the presence of liquid fluids. This distinction is vital for understanding how volcanic systems behave and evolve over time.

Sergio Gammaldi, a researcher at the Vesuvian Observatory of INGV, explained that this variation in fluid state is influenced by pressure, with fluids remaining liquid at greater depths while transitioning to gas closer to the surface. Additionally, the study successfully identified the primary magma conduit, the pathway through which lava and gas ascended during the eruption. This discovery is essential for predicting how future eruptions may unfold and for assessing the associated risks to nearby communities.

Implications for Future Volcanic Activity

The three-dimensional image produced from the study reveals a volume of 15.62 km³, equivalent to a cube measuring 2.5 kilometers on each side. This representation is the first of its kind for a recently formed monogenetic volcano, marking a significant milestone in volcanic research. The detailed mapping of the volcano’s internal structure provides a foundation for future studies and monitoring efforts.

The research underscores the rapid development of the hydrothermal system beneath the young volcano, which includes groundwater and gas. These insights are invaluable for predicting and monitoring future eruptions, not only in La Palma but also in other regions with similar volcanic characteristics. Understanding the hydrothermal dynamics can help scientists develop more accurate models for volcanic behavior, which is crucial for disaster preparedness and risk mitigation.

D’Auria concluded that studying a newly formed volcano from within presents a scientific challenge that significantly enhances the ability to mitigate risks in populated areas. The findings from this research will contribute to a better understanding of volcanic systems and improve the methodologies used for monitoring and predicting volcanic activity.

Key points

• Over 17,000 microearthquakes were recorded following the Cumbre Vieja eruption.
• The study was published in Geophysical Research Letters.
• Research was conducted by INGV and Involcan.
• The eruption began on September 19, 2021.
• Seismic tomography was used to create a 3D map of the volcano’s internal structures.
• The volume of the volcano’s internal structure is 15.62 km³.
• The study aids in predicting future volcanic activity.