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Hekla

Hekla is an active stratovolcano that is located southern Iceland and is part of a volcanic ridge that extends over an area of twenty-five miles. This volcano reaches an elevation of 4,882 feet and holds a unique shape that is a mixture of a stratovolcano and crater row, a trait that is found in very few volcanoes. Its name is translated as “hooded” but it also refers to a hooded cloak, so it is thought that the name could be inspired by the cloud cover that often occurs around the summit. Hekla is one of Iceland’s most active volcanoes, but it does remain quiet for enough time to accumulate small glaciers. The first recorded eruption from this volcano occurred in 1104 and it has produced between twenty and thirty notable eruptions since that time. The time and magnitude of the eruptions are difficult to predict, but it is thought that a longer period of dormancy leads to a larger eruption.

Hekla produced one of the largest volcanic eruptions of the Holocene in 950 BC or 1159 BC. This eruption was rated as a 5 on the Volcanic Explosivity Index and is thought to have released so much ash that the air around the area would have been significantly cooler for many years. Many other VEI 5 eruptions, along with VEI 4 eruptions, occurred in 1104, 1158, 1222, and between 1300 and 1301, among many other years. Other eruptions, which were primarily smaller, occurred between 1341 and 1991, most of which were destructive to animals, land, or human settlements.

One of the most notable modern eruptions of Hekla occurred between 1947 and 1948. It is thought to be the second largest eruption in the world between the years of 1900 and 1970. The first hours of the eruption were Plinian, while rest of the eruption was categorized as Vesuvian. The ash cloud that was released extended eighteen miles into the air by 7:10 AM, after which the wind blew the cloud to Eyjafjallajökull glacier and turned it black. The volcano produced tephra and lava explosions for the next few days and underwent several changes in intensity throughout the rest of the year. This eruption was classified as a VEI 4, while the next few eruptions were slightly less intense at a rating of VEI 3.

Hekla produced its most recent eruption in 2000, and although it was relatively short lived, it was rated as a VEI 3 eruption. It underwent four stages, beginning with explosive activity that was followed by fire fountains and spurts of strombolian activity and finally ending with the release of lava flows. It was thought that Hekla was unable of producing dangerous pyroclastic flows until this eruption, when evidence of these flows was found extending down its side for 3.1 miles. Because of this, it is suggested that people do not attempt to obtain a close look of the volcano during eruption periods.

The area around Hekla once held forests, but the frequency of damaging volcanic activity and human encroachment has changed the landscape and it is no longer able to sustain large amounts of grasses or trees. A program has been introduced that would allow the area to sustain a larger biodiversity and stabilize the soil around the volcano. Known as Hekluskógar, this project currently consists of planting 347 square miles of birch and willow trees on Hekla’s slopes.

Although Hekla produced a large eruption fairly recently, it is a popular destination for tourists, who can partake in hiking, mountain climbing, and skiing during the winter. The volcano features many trails and a visitor center that opened in 2007. In early 2010, signs of a possible eruption were reported including increasing pressure within the magma chamber and a decrease in snow cover near the summit.  In 2013, a group of seven earthquakes caused a Civil Protection State of Uncertainty to be announced and tourist activities were cautioned against. In April of that same year, more activity was recorded that some say is indicative of a future eruption.

Image Caption: The volcano Hekla and Icelandic horse. Credit: Lydur Skulason/Wikipedia (CC BY 2.0)

Hekla


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