Mystery Behind Rare Type of Lava That Continues to Move Even a Year After Eruption Solved [VIDEO]

A team of international scientists has unraveled the mystery of how a rare type of lava continues to move even a year after eruption.

The research was led by Dr. Hugh Tuffen and Dr. Mike James from the Lancaster Environment Centre at Lancaster University. When the researchers visited the Puyehue-Cordon Caulle volcano in Chile in January 2013, they noticed that the obsidian lava flow was still moving even though the volcano became inactive after April 2012.

Dr Tuffen said in a statement, "We found out that the lava was still oozing after almost a year and it advances between 1 and 3 metres a day. Although it moves slowly, it could speed up or collapse if it were to reach a steep hill...."

The Obsidian lava is extremely thick due to which it can barely flow. Its movement is similar to that of a glacier and it is rich in silica that forms a natural glass called obsidian that solidifies on cooling. This forms a rock like covering over the oozing lava.

The team has come up with  a model to explain the movement of the obsidian lava. Dr Tuffen says, "It looks like a solid cliff of crumbling rock up to 40 metres thick, that's as thick as ten double-decker buses, but we found that hidden beneath this crust there is hot, slowly-flowing lava, at up to 900 °C, which can burst out of the edges of the lava flow and help it move forwards. This was previously thought to only occur in hot red flowing or basalt lava, but we have found that thick obsidian lava is actually pretty similar to its runnier cousins."

In recent years the obsidian lava flow was seen in the last three eruptions at Puyehue-Cordón Caulle volcano in Chile in 2011, 1960 and 1921.

The obsidian from the lava flows is found worldwide at several archaeological sites as it a highly prized and traded material that is used in knives, cutting tools and arrowheads.

The details of this finding are published in the journal Nature Communications.