Magma comes from an Italian word that means a thick, pasty substance, which is how molten rock behaves within the Earth.
Lava, another Italian word, means to slide, which is what molten rock does once it reaches the surface.
Pu`u `Ō `ō cone, September 1983. Image courtesy of the USGS Hawaiian Volcano Observatory.
All magma contains dissolved gases. As it rises to the surface, the pressure is reduced and the dissolved gases can escape. If the lava is runny (not viscous), the gases can escape easily and the lava will just run down the landscape (somewhat like syrup).
However, if the lava is thick and pasty (highly viscous), the gases cannot escape and they build up tremendous pressure (like a shaken soda bottle) causing the volcano to erupt/explode violently forming volcanic ash, dust, pumice, etc., and lava.
Volcanoes with reported activity last week include:
Nyamuragira, Democratic Republic of Congo | Suwanose-jima, Ryukyu Islands (Japan) | Tungurahua, Ecuador | Turrialba, Costa Rica | Zubair Group, Yemen | Fuego, Guatemala | Hierro, Canary Islands (Spain) | Karymsky, Eastern Kamchatka (Russia) | Kilauea, Hawaii (USA) | Kizimen, Eastern Kamchatka (Russia) | Popocatépetl, México |Puyehue-Cordón Caulle, Central Chile | Sakura-jima, Kyushu | Santa María, Guatemala | Shiveluch, Central Kamchatka (Russia)
As always, you can view detailed reports with loads of additional background information at the Smithsonian/USGS Global Volcanism Program at:
“For more than 35 years we have been uncertain about the role of volcanic activity on Mercury,” said James W, Head III, professor of geological sciences at Brown University.
But no more.
The MESSENGER team confirmed, in a recent Science Paper, that Mercury’s northern latitudes are covered in smooth plains which show several flow features along the margins and embay or cover several impact craters. These flows are massive covering 6 percent of Mercury’s surface, an area that would cover nearly 60 percent of the continental United States, and are similar to flood basalt eruptions on Earth.
Watch MESSENGER PI, Sean Solomon, present an overview of the new discoveries here. For even more detail, watch both oral presentations (The View From Orbit II & III) from this years AGU Meeting. (You will have to scroll to get to the right presentations)
Want a guided tour of Mercury? Now you can have one in Google Earth!!
Find out how on the MESSENGER website here!
MESSENGER (MErcury Surface, Space ENvironment, GEochemistry, and Ranging) is a NASA-sponsored scientific investigation of the planet Mercury and the first space mission designed to orbit the planet closest to the Sun. The MESSENGER spacecraft launched on August 3, 2004, and entered orbit about Mercury on March 17, 2011
The largest volcano in the world, Mauna Loa in Hawaii which is estimated at around 80,000 cubic kilometers. Peter Lipman of the U.S. Geological Survey used high resolution bathymetry of the underwater slopes of the volcano, data from seismic profiling and gravity studies, and the subsidence rate of Mauna Loa to define the shape and density of the buried part of the volcano. The enormous volcano covers half of the Island of Hawai`i and by itself amounts to about 85 percent of all the other Hawaiian Islands combined!!
Want to see what it looks like from the summit right now??
Volcanoes with reported activity last week include:
Etna, Sicily (Italy) | Galeras, Colombia | Lewotolo, Lomblen Island (Indonesia) |Láscar, Northern Chile | Nyamuragira, Democratic Republic of Congo | Reventador, Ecuador | Sangay, Ecuador | Tungurahua, Ecuador | Zubair Group, Yemen
Ongoing Activity: | Fuego, Guatemala | Hierro, Canary Islands (Spain) | Karymsky, Eastern Kamchatka (Russia) | Kilauea, Hawaii (USA) | Kizimen, Eastern Kamchatka (Russia) | Popocatépetl, México |Puyehue-Cordón Caulle, Central Chile | Sakura-jima, Kyushu | Santa María, Guatemala | Shiveluch, Central Kamchatka (Russia)
As always, you can view detailed reports with loads of additional background information at the Smithsonian/USGS Global Volcanism Program at:
NASA’s Earth Observatory has just posted some great images of Africa’s Nyamuragira volcano and new lava flow produced by the latest activity there. As the Eruptions! blog noted in November, this volcano is remote and poses no threat to people (though there are endangered gorillas that live nearby). The satellite images were taken by the Advanced Land Imager (ALI) aboard the Earth Observing-1 (EO-1) satellite.
There have not been any eruptions in Australia during this century. The most recent eruption in Australia was at Mt. Gambier, a shield volcano in the Newer Volcanic Province, Victoria. The Newer Volcanics Province in Victoria Australia is made of four shield volcanoes and associated vents: Red Rock, Mt. Napier, Mt. Schank, and Mt. Gambier. They last erupted between 5850 and 2900 B.C. The eruptions were explosive and some generated lava flows. It is impossible to say if the volcanoes will erupt again. However, there have been rare earthquakes in the area.
Get more information on Mt. Gambier here
There are numerous other interesting volcanic provinces in Australia. There are flood basalts of Cambrian age (about 650 million years old) northeast of Halls Crossing in northern Australia. Volcanism commenced about 70 million years ago at volcanic centers in southeast Queensland and northeast South Wales. Compositions range from basalt to rhyolite and includes shields, plugs, and domes. In north Queensland there are some very long basaltic lava flows. For example, at Undara a flow is 100 miles (160 km) long! There are also numerous volcanic islands north and east of Australia including North Island, New Zealand, the islands of Vanuatu, the Solomon Islands, New Britian, and Indonesia.
Some other additional sources of information:
Volcanoes with activity this week include:
Callaqui, Central Chile | Cleveland, Chuginadak Island | Galeras, Colombia |Gamalama, Halmahera | Lewotolo, Lomblen Island (Indonesia) | Lokon-Empung, Sulawesi | Poás, Costa Rica | Sorikmarapi, Sumatra (Indonesia) | Tungurahua, Ecuador
Ongoing Activity: | Fuego, Guatemala | Hierro, Canary Islands (Spain) | Karymsky, Eastern Kamchatka (Russia) | Kilauea, Hawaii (USA) | Kizimen, Eastern Kamchatka (Russia) | Popocatépetl, México |Puyehue-Cordón Caulle, Central Chile | Sakura-jima, Kyushu | Shiveluch, Central Kamchatka (Russia)
As always, you can view detailed reports with loads of additional background information at the Smithsonian/USGS Global Volcanism Program at:
Venus has more volcanoes than any other planet in the solar system. Over 1600 major volcanoes or volcanic features are known (see map), and there are many, many more smaller volcanoes.
Locations after Head et al. (1992) J. Geophys. Res. 97, 13153.
Base map is Magellan topography data, available at NASA’s JPL.
Click here to check out the variety of cool strange volcanic features on Venus!
