Erupción volcánica

The Operational Land Imager (OLI) on the Landsat 8 satellite acquired this top image of Mount Etna on December 28, 2018. The image highlights the active vent and thermal infrared signature from lava flows, which can be seen near the newly formed fissure on the southeastern side of the volcano. The image was created with data from OLI (bands 4-3-2) and the Thermal Infrared Sensor (TIRS) on Landsat 8. Image: NASA.

Definition

A type of volcanic event near an opening/vent in the Earth’s surface including volcanic eruptions of lava, ash, hot vapour, gas, and pyroclastic material (IRDR Glossary).

The majority of volcanoes in the world form along the boundaries of Earth's tectonic plates. When tectonic plates collide, one often plunges deep below the other in what's known as a subduction zone. Not all volcanoes are related to subduction: another way volcanoes can form is what's known as hotspot volcanism. In this situation, a zone of magmatic activity—or a hotspot—in the middle of a tectonic plate can push up through the crust to form a volcano. Although the hotspot itself is thought to be largely stationary, the tectonic plates continue their slow march, building a line of volcanoes or islands on the surface (National Geographic).

A volcano is currently active if it is erupting lava, releasing gas or generating seismic activity. An active volcano is labelled dormant if it has not erupted for a long time but could erupt again in the future. When a volcano has been dormant for more than 10 000 years, it is considered extinct. Volcanoes can remain inactive, or dormant, for hundreds or thousands of years before erupting again. During this time, they can become covered by vegetation, making them difficult to identify.

How explosive a volcanic eruption is depends on how easily magma can flow or trap gas. If magma is able to trap a large amount of gas, it can produce explosive eruptions. (Australian Government).

Facts and figures

Over the last 11,500 years, more than 1,500 major eruptions have occurred, with approximately 500 in the Pacific "Ring of Fire" alone (PreventionWeb).

There are volcanoes on every continent, even Antarctica. Some 1,500 volcanoes are still considered potentially active around the world today; 161 of those—over 10 percent—sit within the boundaries of the United States (National Geographic).

There are different types of eruptive events. We can distinguish between primary and secondary events.

Primary events are:

Pyroclastic explosions
Hot ash releases
Lava flows
Gas emissions
Glowing avalanches (gas and ash releases)

Secondary events are:

Melting ice, snow and rain accompanying eruptions are likely to provoke floods and hot mudflows (or lahars)
Hot ash releases can start fires (WHO).

Volcanoes can have many different appearances. The shape of a volcano provides clues to the type and size of eruption that occurred. Eruption types and sizes depend on what the magma is made up of. Three common volcano forms are:

Shield volcano: have a broad, flattened dome-like shape created by layers of hot and runny lava flowing over its surface and cooling.
Composite volcano : also known as stratovolcanoes, they are formed from explosive eruptions. These eruptions create steep sided cones.
Caldera volcano: these volcanoes erupt so explosively that little material builds up near the vent. Eruptions partly or entirely empty the underlying magma chamber which leaves the region around the vent unsupported, causing it to sink or collapse under its own weight. The resulting basin-shaped depression is roughly circular and is usually several kilometres or more in diameter (Australian Government).

Further information

COMET Recent Research page

European Commission's Handbook for Volcanic Risk Management

VolFilm

The Telegraph’s Map of World’s Volcanoes

Volcanic eruptions and their repose, unrest, precursors, and timing

UN-SPIDER Regional Support Offices with hazard-specific expertise

Title: Oficina Regional de Apoyo Argentina

Title: Oficina Regional de Apoyo de Alemania

Title: Oficina Regional de Apoyo de Grecia

Title: Oficina Regional de Apoyo de Indonesia

Related content on the Knowledge Portal

UN-SPIDER conducts Technical Advisory Mission to Peru

, ,

As part of it advisory support activities, UN-SPIDER is carrying out out a Technical Advisory Mission (TAM) to Peru from 1 to 5 April to evaluate the current and potential use of space-based information in all aspects of disaster management. Based on exchanges with a wide range of stakeholders, UN-SPIDER will provide recommendations as to how to strengthen the use of space-based information in disaster risk management and emergency response in the country.
The team of experts led by UN-SPIDER is conducting multiple activities and institutional visits in Lima. The team is comprised of eight experts from UN-SPIDER; the German Aerospace Centre (DLR); the Argentinian National Space Activities Commission (CONAE); the Mexican Space Agency (AEM); the Agustin Codazzi Geographic Institute of Colombia (IGAC); the Santa Maria...
read more

Regional Support Offices mentioned:
Argentina Regional Support Office, Colombia Regional Support Office, Mexico Regional Support Office
01/04/2019
Radar imagery supports analysis of Bali volcano eruption

A team of scientists, led by the University of Bristol’s School of Earth Sciences, has used Sentinel-1 satellite imagery to analyze the ground deformation of the Agung volcano in Bali, Indonesia, and explain why it erupted in November 2017 after 50 years of dormancy.
The previous eruption of Agung in 1963 killed nearly 2,000 people and was followed by a small eruption of its neighbouring volcano, Batur. Because this past event was among the deadliest volcanic eruptions of the 20th century, the scientific community deployed a great effort into the monitoring and understanding of the re-awakening of Agung.
Two months before the eruption, a sudden increase in the number of small earthquakes occurred around the volcano. The researchers realized satellite images could reveal the volcanic ground deformation that occurred prior to the 2017 eruption. From satellite imagery and 3D numerical models...
read more

06/03/2019
Monitoring Volcanoes and Magma Movements

The free online course, provided by the University of Iceland, gives an introduction to volcano monitoring techniques, magma movements and volcano unrest. It presents some aspects of why volcanoes are dangerous and volcanic hazards.

As magma, molten rock inside volcanoes, approaches the surface it releases volcanic gas that finds its way to the surface, and geothermal activity can change. In addition to ground-based techniques, satellite observations are extensively used. The main monitoring techniques for volcanoes are explained in the course, with the aim that students understand both the concept of volcanic unrest and how it can be monitored, how eruptions can be monitored, and signs of volcanic eruptions as seen on instruments.

Understanding the possibilities and limitations of present-day volcano monitoring for detecting magma movements is an important step in understanding volcanoes, evaluating...
read more
Global Volcanism Program database (GVP - Smithsonian Institution)

The Global Volcanism Program database currently contains 1432 volcanoes with eruptions during the Holocene period (approximately the last 10,000 years). Primary names are sorted below in alphabetical order. Please use the volcano search page to find other names and create a list with synonyms and subfeatures.
Publishing institution:
1. Smithsonian Institution - National Museum of Natural History
MoveBank - ICARUS (Max Planck Institute for Ornithology)

Movebank is a free, online database of animal tracking data hosted by the Max Planck Institute for Ornithology. The institute help animal tracking researchers to manage, share, protect, analyze, and archive their data. The animal tracking data in Movebank belongs to researchers all over the world who choose whether and how to share their data with the public. Curretnr esearch is being done on animal derived early warning systems for earthquakes, volcanoes and landslides.
Publishing institution:
1. Max Planck Institute for Ornithology
Thematic Exploitation Platform (TEP - ESA)

ESA's Earth Observation Thematic Exploitation Platform (TEP) is a browser for satellite imagery and specific products on an environmental topic. The TEP platforms are divided into 7 categories: Coastal; Forstry; Geohazards; Hydrology; Polar; Urban; and Food Security. Each platform is a collaborative, virtual work environment providing access to EO data and the tools, processors and Information and Communication Technology resources required to work with them. TEP aims to bridge the gap between the users and the data and tools.
Publishing institution:
1. European Space Agency (ESA)
AIRBUS data set

Pleidas, TerraSar-X, SPOT and Elevation data available commercially from airbus, certain sample data sets at various locations available for free.
Publishing institution:
1. Airbus Defence & Space
Radiant Earth (Radiant Earth Foundation)

The website: https://www.radiant.earth
Help and Tutorials: https://help.radiant.earth/
Demos & Use Cases: https://demos.radiant.earth/
Publishing institution:
1. Radiant Earth Foundation
EarthData (NASA)

NASA's Earth Observing System Data and Information System (EOSDIS) is a program for archiving and distributing Earth science data from multiple missions to users.
Publishing institution:
1. NASA Earth Science Disasters Program
EUMETSAT Image Gallery

Map Viewer that allows downloading and time series creation of meteosat products.
Publishing institution:
1. European Organization for the Exploitation of Meteorological Satellites (EUMETSAT)