Virtual Volcano Vacation #75 WINNERS! – Krafla

krafla cover

Steams at Krafla, June 2007 – Photo by user:Nicolamquin [GFDL (http://www.gnu.org/copyleft/fdl.html) or CC BY-SA 3.0 (http://creativecommons.org/licenses/by-sa/3.0)%5D, via Wikimedia Commons

Of all the volcanoes I have visited, this one has somehow within its system gathered up just about every feature I love in a volcano with the exception of a lava lake. There are domes, a crater lake, large flows of basalt, crater rows, thermals and even welded tuffs. If ever there was a Disneyland of volcanoes, it would likely be Krafla.

Krafla is in many ways your typical Icelandic volcano. There is a central volcano flanked by northeast to southwest trending fissure swarms. There are overlapping lava flows, several distinct crater rows, and thermal vents. From the sky, the most recent lava flow, emplaced in the 1970s and ’80s, appears as a dark grey stain across the lighter surrounding landscape. A bit less obvious is the shape of the various lava flows that were laid down in the early part of the 18th century.

krafla sat map

Satellite view of Krafla in Google Earth, including subfeature placemarks from Global Volcanism Program

 

 

krafla 84 lava

Scientists investigating a slow-moving lava flow at Katla’s Leihrnjúkur fissure on 5 September 1984, the day after the eruption began. – Photo by Michael Ryan, 1984 (U.S. Geological Survey) – Image found at GVP

One popular tourist attraction is Viti, a crater which was formed during the great “Myvatn Fires” eruption of 1724. It is about 300 m in diamter and began its life as a bubbling mud cauldron. Now it has somewhat settled down geothermally and is filled with a bluegreen lake.

krafla viti

Krafla’s own Viti Lake within a maar – Photo by Christian Wirth, de:Wirthi (Own work) [CC BY-SA 2.5 (http://creativecommons.org/licenses/by-sa/2.5)%5D, via Wikimedia Commons

Also there is Leirhnjúkur Lava Fields, a particularly scenic and colourful as well as geothermally active part of the lava flow, another favourite destinations for tourists who want to trek through an active volcano.

krafla leirnijukur

Mud pots and hot springs around Krafla’s Leirnijukur mountain – Photo by Ingibjörg Kaldal – Image found at Geothermal.is

But two things that make Krafla of special interest to me are things that are not so much regarded as tourist attractions. Around 100,000 years ago, a large caldera formed at Krafla. Though it has long since been nearly filled in by subsequent volcanic activity to the point of being almost topographically imperceivable, study of the various rock types of the area have revealed its parameters. It is roughly 10 km in diameter, and in several places along its borders lie welded tuffs that were laid down as airfall deposits. And as an added curiosity in a land known for copious eruptions of basalt, their composition is rhyolitic.

 

krafla tuffs

Map of Krafla caldera and surrounding area showing rock types erupted during different phases – From “Rhyolite volcanism in the Krafla central volcano, north-east Iceland”, by K. Jónasson, Bulletin of Volcanology, December 1994, volume 56, Issue 6 – found at Springer.com

krafla lava dome

View of the Krafla central volcano from the south, on the left is Hlidarfjall, a rhyolitic lava dome. – Photo by Michael Ryan, 1984 (U.S. Geological Survey) – Image found at Global Volcanism Program

But wait, there’s MORE! Two man-made wonderments can also be found at Krafla!

One is the Krafla Power Station, a 60 megawatt geothermal power generating plant and one of the five largest such plant in Iceland. It generates electricity via two steam-driven turbines which are supplied by  boreholes that tap the Earth’s crust as deep as 2 km where superhot rock and deep pressurized natural reservoirs of water interact.

The video below includes scenes around Viti as well as a glimpse of the Krafla Power Station in operation

The other is the Iceland Deep Drilling Project, whose goal is to tap the Earth at 4 km where temperatures are around 400 C and explore supercritical hydrothermal fluids (fluids under such pressure that they exhibit properties of both liquid and gas) as a means of more efficient harvesting of geothermal energy.

This video goes into a little more detail about geothermal energy and how it is generated in Iceland and other places.

This week, Jonet found me first, with Leslie not too far behind and Jesper soon after. Thank you all for finding me, and to everyone who joins the search. This coming Monday, same Volcanohead-time…same Volcanohead channel…I will be celebrating my birthday with a new adventure at a new volcano.

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