Global Volcano Early Warning and Eruption Response from Space (GVEWERS)

GVEWERS is a permanent and sustainable effort intended to support volcano hazards assessment and risk mitigation globally. The initiative builds on previous CEOS activities that started with a Pilot (2014-2017) and continued with a Demonstrator (2019-2023), which showcased how open, low-latency satellite data can aid responses to volcanic eruptions and related hazards. Community-endorsed remote sensing goals for volcano monitoring include:

Daily monitoring of volcanic gas and thermal emissions from space is already feasible thanks to the growing constellation of Earth-observing satellites, particularly those designed for meteorological applications and high-temporal, but low-spatial, resolutions. Moderate-resolution thermal, visible, and SAR sensors also enable weekly views of most volcanoes worldwide. Lagging behind, however, are high-spatial-resolution synthetic aperture radar (SAR) and optical datasets that are essential for detecting subtle, localized, and rapidly evolving ground deformation and surface changes. Even though high-resolution data could be acquired frequently enough to meet volcano monitoring needs, data collection is often irregular, and imagery is usually not openly available to volcanologists — especially at the low latencies needed for volcano monitoring. Exploitation of high-resolution SAR and optical datasets is therefore a central priority within CEOS volcano remote sensing efforts and the main focus of the GVEWERS initiative.

Over one billion people live within 100 km of a volcano that has erupted at least once in the past ~12,000 years, and about 500 volcanoes worldwide have a historical record of eruptions. Yet only about 35% of those historically active volcanoes are monitored by ground-based instrument networks, even though a key component to forecasting eruptions involves collection and modelling of monitoring data. Fortunately, a comprehensive and global volcano-monitoring system already exists — the constellation of Earth-observing satellites originally designed to track weather conditions, landscape evolution, and environmental changes. Since the 1960s and 1970s, when Earth-observing satellite data began to be available, satellite-based remote sensing has detected unrest or eruptions at over 400 volcanoes worldwide. Today’s satellite platforms offer a wide range of spatial, spectral, and temporal resolutions, facilitating a deeper understanding of the volcanic processes that pose hazards to people and infrastructure. It also provides nearly comprehensive views of every stage of the eruption cycle. With this data, scientists can characterise ground deformation, changes in topography and surface conditions, gas emissions, thermal anomalies, and ash plumes.

Over 100 volcano observatories and institutions worldwide are tasked with producing data and interpretations in support of volcanic hazards assessment and risk mitigation. Low-latency access to high-resolution SAR and optical satellite data provides essential support when these agencies must respond to episodes of volcanic unrest and eruption, particularly with respect to communicating potential public safety implications through alert-level changes that can motivate protective actions, including evacuations.

Because data from many meteorological sensors and moderate-spatial-resolution thermal, visible, and SAR sensors are already freely available, GVEWERS focuses on data and derived products from high-resolution SAR and optical imagery. Critical products include:

While some of these datasets can be collected using ground-based and aerial platforms, data collection can be hazardous and hampered by weather conditions. Satellite remote sensing, in contrast, can provide more comprehensive and consistent coverage. SAR data in particular can penetrate cloud cover, which is often ubiquitous in volcanic areas. Used in combination, satellite, aerial, and ground-based observations provide critical datasets upon which volcano observatories can base alert-level determinations and communications to the public and emergency managers.

GVEWERS makes use of a wide range of satellite systems. In addition to meteorological sensors, such as Himawari-9, and Earth and climate monitoring instruments like MODIS, the project relies upon SAR datasets with varying spatial resolutions, moderate-resolution thermal and visible sensors, and high-resolution optical imagery, including:

One of the clearest examples of the importance of satellite data for volcano surveillance is the 2010 eruption of Merapi in Indonesia. During that crisis, local volcanologists and their international collaborators used near-real-time interpretations of high-resolution SAR data in combination with ground-based monitoring to issue warnings of an impending explosive event. The resulting evacuations probably saved thousands of lives.

GVEWERS aims to build on the global need for comprehensive volcano monitoring from space by making available otherwise restricted datasets, as well as providing technical expertise in processing and interpreting those data. Capacity-building efforts also help countries lacking the necessary infrastructure and training in the use of remote sensing data for volcano surveillance. Key benefits of CEOS support for volcano monitoring include: