An Indonesian volcano let loose a massive eruption late on Feb. 13, propelling a mushrooming cloud of ash more than 13 miles high. So far, four deaths are confirmed, and more than 56,000 people have been displaced.
The gallery here includes imagery of the eruption of the Kelut volcano (also spelled “Kelud”) from a number of satellites, as well as graphics that explain the origin of the entire Indonesian volcanic chain. Make sure to enlarge each one to get the full effect. Below are additional details about each image.
In the first graphic, a true-color image of the giant eruption cloud alternates with a false-color infra-red picture. Both were captured by the Suomi NPP satellite. The false color scheme is indicative of temperature. The tiny patch of violet in the center shows were temperatures plunged below -80 degrees C as the cloud shot up into the stratosphere.
Next is an animation consisting of imagery and data from MTSAT-2, a Japanese weather satellite. The colors show the different heights to which the eruption cloud rose, with blacks indicative of ash blown to elevations of 20 kilometers or more. (Twenty kilometers is 12.4 miles.)
In addition to shooting up to high elevations, the ash spread widely. The third image, captured by the MODIS instrument on NASA’s Terra satellite, shows the extent of that spread off the southern coast of Java the day after the eruption. The thick yellowish stuff is the ash, and by my measurement it stretches about 500 miles long in this image.
The next image was also captured by MODIS on the Terra satellite — three days before the eruption. Almost all of the island of Java is visible, as well as Bali and Lombok to the east. I’ve labeled 10 volcanoes, but there are actually more. Each of the volcanoes is scarfed with a ring of clouds, making them easier to pick out.
The block diagram that comes next shows the source of those volcanoes: the movement of tectonic plates along a subduction zone, called the Java Trench, offshore of Indonesia. The Indo-Australian plate dives beneath the Eurasian plate, causing magma to rise and create a necklace of volcanoes on the islands of Java, Bali, Lombok and Sumbawa, and beyond.
Lastly, a map of the world’s tectonic plates showing their relative movements and other information. In addition to creating the volcanoes of Indonesia, the movement of the Indo-Australian plate is also responsible for the Himalayas as it pushes inexorably into the underbelly of the Eurasian plate.