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Roger Weller, geology instructor
by Jeannell Hilton
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?
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
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
Photo credit: Andi Rosadi
Why Does This Indonesian Volcano Burn Bright Blue? (n.d.). Retrieved November 24, 2015, from http://www.smithsonianmag.com/science-nature/why-does-indonesian-volcano-burn-bright-blue-180949576/?no-is
Temperature of Lava. (2009, March 25). Retrieved November 24, 2015, from http://www.universetoday.com/27891/temperature-of-lava
Magma. (2011, February 14). Retrieved November 24, 2015, from http://education.nationalgeographic.org/encyclopedia/magma/
Ijen. (n.d.). Retrieved November 24, 2015, from http://www.volcanodiscovery.com/ijen.html
The Three Main Types of Volcanoes. (2015, January 13). Retrieved November 24, 2015, from http://www.zmescience.com/other/science-abc/types-of-volcano/
Lahars and Their Effects. (n.d.). Retrieved November 24, 2015, from http://volcanoes.usgs.gov/hazards/lahar/