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NASA Articles » Monitoring Volcanoes
Monitoring Volcanoes from Space
NASA Satellites Collect Images and Data to Monitor Worldwide Volcanoes.
NASA scientists and their associates at other institutions have developed numerous ways to monitor worldwide volcanoes from satellites for signs of eruption. In addition to satellite images, they have also developed sensors to detect heat, sulfur dioxide and small changes in the shape of earth's surface. Here is a small collection of images that show different types of volcano monitoring, all done from satellites.
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This is a false-color image of an area in the Democratic Republic of the Congo captured on January 31, 2007. Two volcanoes, Nyamuragira and Nyiragongo, with relatively recent lava flows can be seen in the image. About one year before this image was captured, an eruption of Nyiragongo sent a destructive lava flow through the town of Goma. Nyiragongo is a relatively steep volcano and the lava flows remain narrow and contained within the channels of the steep terrain. Nyamuragira has much gentler slopes and the lava flows spread out over broad areas. A new vent on the south flank of Nyamuragira sent a lava flow into the outskirts of the town of Sake. This image reveals two signs of current activity at Nyiragongo. The bright pink dot at the summit is where the satellite sensor detects elevated surface temperatures. And the bright blue haze streaming to the west of the vent is a volcanic plume of vapor and ash released from Nyiragongo. The bright white areas are clouds. Image and caption adapted from NASA.
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Sicily’s Mount Etna released a thick plume of volcanic ash on November 24, 2006. According to news reports, the volcanic activity forced an overnight closure of the Fontanarossa Airport, the main airport in eastern Sicily. The Moderate Resolution Imaging Spectroradiometer (MODIS) flying onboard NASA’s Aqua satellite took this picture on November 24. In this image, a dark reddish-brown plume blows away from the volcano’s summit toward the southeast, gradually dissipating as it goes. At the summit, MODIS has detected a hotspot, indicating surface temperatures much warmer than the surroundings. The bright blue color of the southern coastal waters off the island are probably due to sediment either churned up by wave action or emptied into the sea by heavy runoff from rivers and streams. The island experienced storms with heavy rain in the days preceding the image. Sediment is reflective, and it colors the shallower waters turquoise. Image and caption adapted from NASA. |
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This is an image of an area of the Pacific Ocean around Anatahan Island, one of the Northern Mariana Islands. It was captured shortly after midnight on February 7, 2008. Although it was dark when the image was captured the satellite was equipped with a thermal emission and reflection radiometer. This instrument is sensitive to wavelengths of radiation associated with heat and the images produced are "heat maps". Dark areas on the image are cool and white areas on the image are warmer. The outline of Anatahan Island is drawn with a white line for reference. The darkest areas on the image are cloud-tops and the light blue areas are cloud-free Pacific Ocean. A bright spot on Anatahan is volcanic heat in the caldera of Anatahan Volcano. The purple haze streaming from the hot spot to the west is an ash plume from the Anatahan vent. Monitoring volcanoes for signs of eruption is very important. The ash and gases released from a volcano can be a hazard to aviation and present an air quality threat to populated areas downwind. Image and caption adapted from NASA. |
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Soufriere Hills Volcano on Montserrat Island in the Caribbean produced an explosive eruption on the morning of May 20, 2006. This eruption sent about 90 million cubic meters of material down the slopes and into the atmosphere. Avalanches of mud and rock swept down stream channels and into the ocean. And, a cloud of ash and volcanic gas pushed up over 17 kilometers (55,000 feet) into the atmosphere. An infrared sounder on NASA's Aqua satellite was able to detect the cloud on three different passes over this region. Soufriere Hills Volcano can be seen on the above map, near the eastern margin. About one day after the eruption on May 21, Aqua detected the ash cloud south of Puerto Rico, about 250 miles (400 kilometers) west of Montserrat Island. The following day, May 22, the cloud was south of Jamaica, about 1000 miles (1600 kilometers) west of Montserrat Island. The third day after the eruption the cloud was over San Salvador and its concentration and detectable size was significantly reduced. Airliners were directed around this cloud as it progressed across the Caribbean and over the Pacific. Image and caption adapted from NASA. |
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Scientists at the U.S. Geological Survey (USGS) use radar signals broadcast from a satellite to detect, measure and monitor small changes in the shape of Earth's surface. By bouncing the radar signal off of the surface, and detecting the return signal, they can make a very accurate topographic map. If they collect this information on multiple passes of the satellite they can compare them over time to detect change. The image above is a map of topographic change in the area surrounding Three Sisters Volcanoes (shown as red triangles). Colors on the map represent different degrees of elevation change. The bulls-eye pattern centered just southwest of the volcanoes is an area of uplift. During a four year period (1997-2001) the area was lifted about 15 centimeters (6 inches). This uplift is thought to be caused by a magma intrusion. The yellow circles are epicenters of an earthquake swarm that could be associated with this motion. Image and caption adapted from USGS. |
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The above are just a few ways that NASA and USGS scientists are monitoring volcanoes with satellite data. Over time they will undoubtedly develop other methods that might be used for hazard mitigation, geothermal resource development and more.
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