The Volcanic Information System: Long-Range Infrasound Monitoring of Volcanic Eruptions With Open-Access Datasets And Year-Long Back-Azimuth Deviation Bias Predictions

Energetic volcanic eruptions can inject large amounts of ash into the atmosphere, posing a direct threat to commercial flights and potentially overwhelming populations down the ash plume path. These eruptions also produce infrasound –acoustic waves below 20 Hz– which can propagate over hundreds to thousands of kilometers in the atmosphere due to favorable ducting conditions and its intrinsic low attenuation.

Within the Atmospheric dynamics Research InfraStructure in Europe (ARISE) project (FP7, H2020), in collaboration with the Toulouse Volcanic Ash Advisory Centre (VAAC), the Volcanic Information System (VIS) was created as a prototype monitoring system that uses long-range (>250 km) infrasound recordings to remotely detect and notify of explosive eruptions.

The VIS was designed to primarily use data recorded by the global International Monitoring System (IMS) infrasound network (53 stations of 60 planned stations), but it can also include non-IMS arrays (e.g., AMT, Florence, Italy) to increase the coverage. At its core, the VIS relies on a data processing output denoted the Infrasound Parameter (IP) to establish when an eruption occurs. The IP value accounts for propagation effects, detection persistency, and infrasound signal amplitude.

Currently, we are thoroughly testing the capabilities of the VIS, and considering the future developments that can be implemented to improve its reliability, before it is made publicly available.

Our recent efforts have expanded the VIS capabilities to use open-access (OA) streamlined and standardized IMS-derived infrasound array signal processing data products. We found that the eruption notification results using OA data were comparable to the notifications calculated with regular IMS data (i.e., PMCC detections).

In this work, we look in detail into the eruptive periods of April 2010 Eyjafjallajökull (Iceland), May 2016 Etna (Italy), and April 2021 La Soufrière (Saint Vincent island, Saint Vincent and the Grenadines), and test how year-long back-azimuth deviation predictions (i.e., pre-calculated back-azimuth bias values) for the nearest IMS stations (<2500 km) can help decreasing the eruption notification false positives and improve the VIS overall reliability. We compare the VIS notification results with detections calculated using both OA and PMCC data, and incorporate the available HOTVOLC webGIS satellite notifications (2010-2022), plus other available eruption catalogues (e.g., Global Volcanism Program). We present a preliminary eruption catalogue for these cases, and show to what extent infrasound-only, and infrasound+satellite monitoring (ASH2/ASH5 products from HOTVOLC) can achieve reliable eruption notifications in the studied areas.

As part of the European Geo-INQUIRE project (HORIZON-INFRA-2021-SERV-01), the VIS will be integrated into the Thematic Core Service Volcano Observation (TCS-VO) of the European Plate Observing System (EPOS). Future developments will also include integration into web services such as the HOTVOLC web-GIS interface (OPGC, CNRS-INSU) or the EPOS Data Portal.