The Earth Story

Active crater at Kilauea caldera

Press report on an adventurer spending a night near the lava lake at one of the volcanoes in Vanuatu

I can’t “not” share this tour around the current lava flows at Kilauea from Paradise Helicopters. Even get narration in the captioning! Gorgeous view of the current growing lava delta towards the end.

Classic video of Katia Kraft - volcanologist who traveled the world visiting eruptions and eventually was killed in a pyroclastic flow in Japan. This lava flow was at Katla volcano, Iceland. 

View of Mt. St. Helens from Johnson Ridge Observatory. Trees in the foreground almost certainly knocked down in the 1980 eruption.

Volcanic Avalanche

Volcanoes have this annoying habit of becoming unstable. They build themselves up vertically, piling up lava flows on the top of the cone, until every so often gravity wins.

Volcanic collapse happens for a number of reasons. The biggest recorded avalanche in modern history happened because of a volcano; the entire north side of Mount St. Helens collapsed in 1980 due to pressure within the volcano that was deforming the entire mountain.

Other types of collapses are associated with the building of a high peak or a lava dome. When thick, viscous lava is pushed out of a volcano, it starts building lava domes that build upwards. A big, vertical pile of rocks isn’t a stable situation and can lead to a collapse.

This image from the International Space Station shows the remnants of an ancient volcanic collapse in the nation of Bolivia. The mountain close to the center of this image is called Tata Sabaya. It’s one of many volcanoes in this part of the world, occurring due to subduction off of the West coast of South America.

However, take a look to the west of this cone. First, you can see the dried, salty remnants of a lakebed called Salar de Coipasa, which was filled with water during the last glacial period (10,000 years or more ago, at the time it would have been Lago Coipasa). Today, that lake has mostly dried up, leaving a salt flat deposit…but there are all these giant pieces of rock sticking out.

These blocks are surrounded by the saline deposits, but they spread over an area of 300 square kilometers. For comparison, that’s over 3 times the size of manhattan. The largest blocks stand up to 100 meters above the surrounding terrain; basically they’re skyscrapers.

These giant blocks are the remnants of a mega-landslide. The Tata Sabaya volcano, sometime before the last glacial maximum, completely collapsed, spilling its innards to the west and into the lake. Whether this collapse happened during an active eruption or just because of gravity (or gravity + an earthquake) is difficult to tell, because all of the other remnants of this avalanche wound up in the lake and washed away. Since the collapse, the volcano has rebuilt itself into a mountain probably similar in size to what it used to be. But at least from this perspective, the remnants of this mega-avalanche are a sight to behold.

-JBB

Image source, from NASA: http://earthobservatory.nasa.gov/IOTD/view.php?id=80945

Tata Sabaya: http://www.volcano.si.edu/world/volcano.cfm?vnum=1505-032

Volcanological and petrological evolution of Volcan Tata Sabaya, SW Bolivia (subscription): http://www.sciencedirect.com/science/article/pii/037702739390043Q

Painted Dunes

These strange and beautiful dunes can be found in the Lassen Volcanic National Park in northeastern California. The park is part of the Cascade Range and has many fascinating geological features to offer such as mud pools, hot springs, gas vents, jagged craters, lava flows and strangely colored dunes.

Over many years volcanic activity has created this interesting area comprised of an impressive landscape containing forests, glaciated valleys, cliffs, lakes, waterfalls and volcanic domes. Lassen Peak, for example, was originally a side vent of a much larger volcano and has erupted several times, most recently in 1915 with a violent explosion. The magma that fuels the volcanoes in the Lassen Volcanic National Park is derived from subduction off the coast of Northern California.

In order to visit the Painted Dunes you have to follow the Cinder Cone Trail leading around Cinder Cone. This volcano last erupted in the 1650s and created a lava flow field composed of basaltic andesite to andesite lava. These flows, also known as “Fantastic Lava Beds”, are in close association with the Painted Dunes.

The Dunes are in fact multicolored pumice fields that were created by the oxidation of volcanic ash, when it was deposited on the lava flows when they were still hot.

Xandi

Image Credit: http://bit.ly/1Ss8A63

Sources: http://on.doi.gov/20ezd4s http://bit.ly/1P4g4b7 http://bit.ly/1P4ht1b