Hekla Volcanic System

Summary Details

The Hekla volcanic system (including the Vatnafjöll fissures) is situated on the western border of the Eastern Volcanic Zone (EVZ). The Hekla system is about 40 km long and 20 km at its widest. The region is mountainous, and reaches a high on the Hekla ridge (1491m). Since the eruption of Hekla 5 about 6000 radiocarbon years BP, the volcano Hekla has produced about 6.7 km3 of acid rocks and 12 km3 of intermediate rocks, but no basalts. Alkali olivine basalts are produced by eruptions away from from Hekla itself. During historical times there have been 18 eruptions, with the most recent being in February of 2000. All major Hekla eruptions occur in Heklugja, the 5.5. km long summit fissure and its extensions to the south-west and north-east. Besides these, many smaller eruptions have occurred on the flanks of Hekla. The Hekla volcano should be regarded as the centre of the fissure swarm, as this is the site of largest productivity and the site where the most evolved rocks are produced. The total amount of lava erupted in the system is 7.7 km3, whilst the volume of a single lava varies from 0.005 to 1.2 km3. For each eruption the initial chemical composition is a roughly linear function of the length of the preceding quiescent period. This relationship is also apparent in the volume of extruded material which indicates a large magma chamber(s). The Vatnafjöll fissures have erupted basaltic lavas and tephras.

Eruptions described in Tephrabase

• Hekla 4 Eruption
• Hekla 3 Eruption
• Hekla 2000
• Hekla 1991
• Hekla 1980
• Hekla 1970
• Hekla 1947
• Hekla 1845
• Hekla 1766
• Hekla 1693
• Hekla 1636
• Hekla 1597
• Hekla 1510
• Hekla 1389
• Hekla 1341
• Hekla 1300
• Hekla 1222
• Hekla 1206
• Hekla 1158
• Hekla 1104 (Hekla 1)

References

Jakobsson, S.P. (1979) Petrology of recent basalts of the Eastern Volcanic Zone, Iceland. Acta Naturalia Islandica  26, 1-103.

Data Sources

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This Tephrabase search was made on 5/8/2025 at 22:39:54 local time, Edinburgh, Scotland, UK.