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Roger Weller, geology instructor

blue lava
by Jeannell Hilton
Physical Geology
Fall 2015

                                              Kawa Ijen: Home of Blue Lava


            Many volcanoes seem to have the familiar characteristic of having a red, orange, and yellow glow to its lava. The reason why the lava gives off such warm hues is because the rock is heated below the surface then expelled out a volcanic vent at about 1,300 to 2,200 degrees Fahrenheit. Below the surface, magma reaches temperatures of 1,292 to 2,372 degrees Fahrenheit.

A spectacular eruption in Stromboli, Italy. Image via Places under the Sun.


Types of Volcanos and Lava

            There are three main types of volcanoes that exist. The first of the three is the composite volcano. This volcano is cone shaped made or layers of hardened lava and cinders. Over time, they both layer on top of each other creating the cone shape. The next volcano is the cinder cone volcano. The shape of the cinder cone is very steep and is composed of deep layers of only tephra from the volcano. Lastly is the shield volcano, who gets its name from the shield-like shape. This volcano is built almost entirely cooled lava vents.

            Rhyolitic lava, is very thick, and when erupted creates lots of energy and power. This thick barely flowing lava is rich in silicates. Basaltic lava is very liquid-like and flows quickly over any path burning everything in its way. Andesitic lava is in between the two previous types of lava. This type of lava forms composite volcanos.

The “gentle” flow of a shield volcano – image via USGS.

         In a few rare cases lava can appear to be a different color, but almost all of the time it does not fall far from the spectrum of reds and oranges. A volcano in East Africa appears to have black lava in the sunlight, but during the night it glows a red orange color. What’s in the lava determines how bright or red the color of the lava will be, but have you ever heard of lava being an electric blue color?


             Photo Credit:

Kawah Ijen’s Location and Geological Structure

       Located in East Java, Indonesia lies a strange but gorgeous volcano that barely caught anyone’s attention until recently. The Ijen volcano is a stratovolcano that stands 9,183 feet high. This volcano houses the world’s largest acidic volcano crater lake called Kawah Ijen. Its waters are a very pretty turquoise color. This crater is active and measures 950x600 meters. Around this area is land rich in Sulphur deposits. These are usually collected but due to the restless activity of the volcano, mining and collection has been shut down. The eruptions are extremely dangerous due to the fact that the lake may drain and form lahars.

Photo Credit: Roland Gerth



            Lahars is an Indonesian term that describes a mixture similar to concrete of hot or cold debris flowing down the volcano at high speeds. These forms of mass wasting can carry partials as fine as clay to large boulders.

 What makes this volcano so special? The large amount of sulphur content in the lava causes it to burn a bright blue color. During the day the blue is not visible, but at night it shows its true colors. The Ijen volcano is a part of a group of small stratovolcanoes all located within the caldera. There are many other volcanos, no longer active that form a ridge over the Ijen volcano.

        Photo credit: Andi Rosadi











Why Does This Indonesian Volcano Burn Bright Blue? (n.d.). Retrieved November 24, 2015, from


Temperature of Lava. (2009, March 25). Retrieved November 24, 2015, from


Magma. (2011, February 14). Retrieved November 24, 2015, from


Ijen. (n.d.). Retrieved November 24, 2015, from


The Three Main Types of Volcanoes. (2015, January 13). Retrieved November 24, 2015, from


Lahars and Their Effects. (n.d.). Retrieved November 24, 2015, from