This time there will be a volcano from the backyard garden. It is located approximately 7 km northeast of Hafnarfjordur. Its last major eruption was about 7,200 years ago. The crater’s lava flowed down to the sea and now covers the area between Hafnarfjörður and Garðabær. If Búrfell had exploded today, it would likely be after IKEA.
A large part Hafnarfjörður he’s standing on this lava. One of its parts is simply called Búrfellshraun, but basically each of the fragments has a separate name – Smyrlabúðarhraun, Gráhelluhraun, Lækjarbotnahraun, Urriðakotshraun, Hafnarfjarðarhraun, Garðahraun and Gálgahraun. The part of the lavatory called Gálgahraun is freely translated “Gallows lava field”because criminals were executed here in the past.
The crater of the Búrfell volcano it lies near the eastern border of the shallow valley that is part of the Trölladyngja volcanic fracture system. The lava field covers approximately 24 km2 and its volume is approximately 0.5 km3. This area belongs to the Krýsuvík volcanic system.
If we had witnessed the Búrfell eruption more than seven thousand years ago, we would have seen three major lava flows. The first is Kaldársel. At the beginning of the eruption, lava flowed south in the open channel, feeding the so-called a parasitic (secondary) lava lake that has formed in the present-day Kringlóttagjá area. On the south side, the Kaldársel stream has disappeared under younger lava. As the eruption progressed, the Búrfell cone increased in height and the level of the lava lake in the crater rose. As a result, the lava crossed the rim of the cone to the southwest, cascading down the slope to the west and forming the Smyrlabúðarhraun. There it split into two parallel branches. The southern one was formed by the flow of lava through the corridor between Sléttuhlíð and Setbergshlíð, forming the Gráhelluhraun, and the narrow lava strip that extends all the way to the center of Hafnarfjörður has disappeared under the lava from the northern arm. The northern arm (largest) ran directly northwest between Vífilstaðarhlíð and Setbergshlíð, then spilled westward to the coast at Hafnarfjörður (as far as Straumsvík) and Skerjafjörður. In the process, lava blocked a small valley and formed the little lake of Urriðakotsvatn. At this stage of the eruption, a 3.5 km long Búrfellsgjá lava bed was created, feeding the northern branch of the lava stream.
The nature protection register states that “Búrfell and the lava channels of Búrfellsgjá and Selgjá, together with a 200 m wide strip on both sides of the gorge, are on the list of protected areas, because there is one of the most unique lava flows in the country”.
Búrfellsgjá located adjacent to a nature reserve Heiðmörk located south of Reykjavik near Hafnarfjörður. It is best to start your hike to Búrfell from the parking lot at Heidmerkurvegur. From Reykjavík city center, take road 40 towards Keflavík. From Vífilsstaðegur we turn left, where after about 3 km it turns into Elliðatnsvegur. After about 2.5 km, we reach Heidmerkurvegur and turn left. Only about 3 km more and we are in the parking lot. Route 408 leads to our volcano from here.
Nearby is Gjáarrétt, a former sheep farm for the farmers of Hafnarfjörður and Álftanes, now historic ruins. The road to Búrfell volcano is easy, it leads through a relatively level lava field to the hillside. Between Búrfell and Helgafell we come across a place called Valahnúkur. There is a cave there, occupied by shepherds around 1940. It was they who planted trees that make up a charming forest today.
Near Kaldársel there are small lakes called Kaldárbotnar. The Kaldá river flowing there disappears into the lava. Legend has it that Kaldá was once a large and abundant river, but when two brothers drowned in it, their father, who was a sorcerer, cursed the river and it fell into a lava field.
The volcano itself rises 180 meters above sea level and is made of a material called scoria (a porous crust on the surface of the lava) and other pyroclastic components. The lava from this crater forms olivine-toleite rocks with beautiful phenocrystals – these are large and well-formed crystals of various minerals – in this case feldspar and olivine.
In the last 1100 years, no new fissures and faults have formed in this area, which means that the tectonic activity in this part has decreased. Although this system looks dormant for now, it is still considered active.
When you get to this extraordinary place, sit in peace and quiet, close your eyes … Maybe you can hear the whispers of Huldufólk – hidden people – there must be a whole lot of them there.
From the series Volcanic alphabet:
- Volcanic alphabet – A for Askja