Volcanic Eruption

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:

  1. Shield volcano: have a broad, flattened dome-like shape created by layers of hot and runny lava flowing over its surface and cooling.
  2. Composite volcano : also known as stratovolcanoes, they are formed from explosive eruptions. These eruptions create steep sided cones.
  3. 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

Related content on the Knowledge Portal

SAM Satellite

ALOS / Daichi

ALOS (Advanced Land Observation Satellite) has been decommissioned. ALOS was successfully launched on January 24, 2006 from the Tanegashima Space Center.

ALOS was one of the world's largest earth observation satellites whose function is to collect global and high resolution land observation data. ALOS data was made available at conditions similar to those of ERS and Envisat missions, namely for scientific 'Category-1' use as well as commercial applications.

The ALOS (renamed "Daichi") satellite sensor had three remote-sensing instruments: the Panchromatic Remote-sensing Instrument for Stereo Mapping (PRISM) and for digital elevation models (DEMs). The Advanced Visible and Near Infrared Radiometer type 2 (AVNIR-2) for precise land coverage observation, and the Phased Array type L-band Synthetic Aperture Radar (PALSAR) for day-and-night and all-weather land observation and enabled precise land coverage... read more

Launch date:
24/01/2006
NOAA-18

NOAA-18, known before launch as NOAA-N, is a weather forecasting satellite run by NOAA. NOAA-N (18) was launched on May 20, 2005, into a sun-synchronous orbit at an altitude of 854 km above the Earth, with an orbital period of 102 minutes. It hosts the AMSU-A, MHS, AVHRR, Space Environment Monitor SEM/2 instrument and High Resolution Infrared Radiation Sounder (HIRS) instruments, as well as the SBUV/2 ozone-monitoring instrument. It is the first NOAA POES satellite to use MHS in place of AMSU-B.

APT transmission frequency is 137.9125 MHz (NOAA-18 changed frequencies with NOAA-19 on June 23, 2009).

Instruments:
AMSU-A (Advanced Microwave Sounding Unit - A)
AVHRR/3 (Advanced Very High Resolution Radiometer / 3)
HIRS/4 (High-resolution Infra Red Sounder / 4)
MHS (Microwave Humidity Sounding)
S&RSAT (Search & Rescue Satellite-Aided Tracking System)
SBUV/2 (Solar Backscatter Ultraviolet / 2)
DCS/2 (Data Collection... read more

Launch date:
20/05/2005
Cartosat-1 / IRS-P5

Cartosat-1 satellite sensor was built by ISRO (Indian Space Research Organization) which is mainly intended for cartographic applications was launched by the PSLV on May 5, 2005 at Sriharikota, India.
Prior to launch, ISRO renamed the IRS-P5 spacecraft to CartoSat-1, to describe more aptly the application spectrum of its observation data. In this mission, the high resolution of the data (2.5 m GSD) is being traded at the expense of multispectral capability and smaller area coverage, with a swath width of 30 km. The data products are intended to be used in DTM (Digital Terrain Model)/DEM (Digital Elevation Model) generation in such applications as cadastral mapping and updating, land use as well as other GIS applications.

Instrument: PAN (Panchromatic Camera)
- high resolution optical imager
- max swath: 30km

Launch date:
05/05/2005
ResourceSat-1 / IRS-P6

IRS-P6 is an Earth observation mission within the IRS (Indian Remote-Sensing Satellite) series of ISRO (Indian Space Research Organization), Bangalore, India. The overall objectives of the IRS-P6 mission (ResourceSat-1) are to provide continued remote sensing data services on an operational basis for integrated land and water resources management. IRS-P6 is the continuation of the IRS-1C/1D missions with considerably enhanced capabilities.

Prior to launch, ISRO renamed the IRS-P6 spacecraft to ResourceSat-1, to describe more aptly the application spectrum of its observation data.

Instruments:
LISS-4 (Linear Imaging Self-Scanning Sensor-4)
LISS-3 (Linear Imaging Self-Scanning Sensor-3)
AWiFS (Advanced Wide Field Sensor)

Launch date:
17/10/2003
NigeriaSat-1

On 26 September 2003 Nigeria launched its $13 million national satellite NigeriaSat-1 in Plesetsk, Russia under a seven-nation constellation being handled by a Russian firm, Cosmos. Nigeriasat-1 is a low earth orbit micro satellite for disaster monitoring looking spacecraft, 5-year target design life-span orbit 700km. The launching of the National Satellite, which started development in November 2001, had been postponed from July 2003 because the Russian Space Agency had to launch a military satellite during that period. NigeriaSat-1 is one of five satellites which will make up a network called the Disaster Monitoring Constellation. The other partners in the international consortium are UK, China, Algeria, Turkey, Thailand and Vietnam. Each satellite belongs to one country, but they will share information with each other when disaster monitoring is needed. The Disaster Monitoring Constellation satellites, which cost less than $10 million each, are built by a British-based company,... read more

Launch date:
27/09/2003
UK-DMC-1 / BNSCSat 1

BNSCSat (British National Space Centre Satellite) or UK-DMC 1 is the UK component of DMC. The Disaster Monitoring Constellation (DMC) is an international programme initially proposed in 1996 and led by SSTL (Surrey Satellite Technology Ltd) from the United Kingdom, to construct a network of five affordable Low Earth Orbit (LEO) microsatellites. The objective is to provide a daily global imaging capability at medium resolution (30-40 m), in 3-4 spectral bands, for rapid-response disaster monitoring and mitigation. The Disaster Monitoring Constellation (DMC) is a novel international co-operation in space, led by SSTL bringing together organisations from seven countries: Algeria, China, Nigeria, Thailand, Turkey, the United Kingdom and Vietnam. The DMC Consortium is forming the first-ever microsatellite constellation bringing remarkable Earth observation capabilities both nationally to the individual satellite owners, and internationally to benefit world-wide humanitarian aid efforts... read more

Launch date:
27/09/2003
SPOT 5

The satellites SPOT 5 (Satellite Probatoire de l'Observation de la Terre) was a third generation of SPOT earth observation satellite operated by Spot Image.

SPOT 5 used the improved SPOT Mk.3 bus design.

The prime imaging instrument was HRG (High Resolution Geometric), which was built by Astrium SAS of Vélizy, France to continue to improve the HRVIR service of SPOT-4. Two HRG instruments are provided in the conventional SPOT-series double-observation configuration, each with a FOV of 4.13º and the same cross-track pointing capabilities of ±27 º as the HRVIR imager on SPOT-4. The observation coverage of each HRG is 60 km in the nadir direction and >80 km in the oblique configuration.

SPOT-5 carries also the HRS (High Resolution Stereoscopic) instrument, which was developed and built by EADS Astrium SAS, sponsored by CNES and SPOT IMAGE. The objective of this instrument is to provide large-area along-track stereoscopic panchromatic imagery with good altimetric... read more

Launch date:
04/05/2002
Terra

Terra explores the connections between Earth's atmosphere, land, snow and ice, ocean, and energy balance to understand Earth's climate and climate change and to map the impact of human activity and natural disasters on communities and ecosystems. It was launched on 18 December 1999 and has far exceeded its design life, having a strong chance of operating successfullty into the early 2020s.
Terra is in a circular sun-synchronous polar orbit that takes it from north to south (on the daylight side of the Earth) every 99 minutes.

On October 6, 2018 Terra completed 100,000 orbits around Earth.

Approximately the size of a small school bus, the Terra satellite carries five instruments that take coincident measurements of the Earth system.

Instruments:
Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER): Creates high resolution images of water, ice, clouds and the land surface using Shortwave Infrared (SWIR... read more

Launch date:
18/12/1999
Landsat 7

The government-owned Landsat 7 was successfully launched on April 15, 1999, from the Western Test Range of Vandenberg Air Force Base, California, on a Delta-II expendable launch vehicle. The Earth observing instrument on Landsat 7, the Enhanced Thematic Mapper Plus (ETM+), replicates the capabilities of the highly successful Thematic Mapper instruments on Landsats 4 and 5.
Landsat 7 is the most accurately calibrated Earth-observing satellite, i.e., its measurements are extremely accurate when compared to the same measurements made on the ground.  Landsat 7’s sensor has been called “the most stable, best characterized Earth observation instrument ever placed in orbit.”  Landsat 7’s rigorous calibration standards have made it the validation choice for many coarse-resolution sensors.
Considered a calibration-triumph, the Landsat 7 mission went flawlessly until May 2003 when a hardware component failure left wedge-shaped spaces of missing data on either side of... read more

Launch date:
15/04/1999
NOAA-15

NOAA-15 (designated NOAA-K before launch) is one of the NASA-provided TIROS series of weather forecasting satellite run by NOAA. It was launched on May 13, 1998, and is currently operational, in a sun-synchronous orbit, 807 km above the Earth, orbiting every 101 minutes. It hosts the AMSU-A and AMSU-B instruments, the AVHRR and High Resolution Infrared Radiation Sounder (HIRS/3) instruments, as well as a Space Environment Monitor (SEM/2).

Instruments:
AMSU-A (Advanced Microwave Sounding Unit - A)
AMSU-B (Advanced Microwave Sounding Unit - B)
AVHRR/3 (Advanced Very High Resolution Radiometer/3)
HIRS/3 (High Resolution Infra Red Sounder/3)
S&RSAT (Search & Rescue Satellite-Aided Tracking System)
DCS/s (Data Collection System/2)
SEM/MEPED (SEM/Medium energy proton detector)
SEM/TED (SEM/Total Energy Detector)

Launch date:
13/05/1998

Pages

Hazard group

Terms in the same hazard group

Zircon - This is a contributing Drupal Theme
Design by WeebPal.