Reykjanes

Reykjanes is a small headland on the south-western end of the Reykjanes Peninsula in Iceland, giving the main peninsula its name. Volcanic action is responsible for forming the entire peninsula. The nearest town is Keflavik.

The name, Reykjanes, translates to "smoking point,” reykja smoking, and nes point. It is named this due to the continuing volcanic activity of the Reykjanes volcanic belt; there are also many other uses of this name in Iceland, e.g. the Reykjanes Peninsula or Reykjanes in Ísafjarðardjúp.

Geography
The region is about 9 km to the south of Iceland's international airport. It is about 25 km2 and includes the Reykjanes volcanic system that extends in a linear fashion up its centre continuing to the north-east as the hill of Sýrfell at 93 m high. Other volcanic systems of the Reykjanes volcanic belt could affect the Reykjanes region and have erupted as recently as 2024. Other hills associated with the system are Skálafell (Grindavíkurbær) with a height of 76 m in the south-west near the sea and Bæjarfell at 69 m high to its north.

The Reykjanesviti lighthouse is on Bæjarfell and is fairly frequently visited by tourists.. The geothermal power station is inland from the lighthouse to its north-east.

Valahnúkamöl is its south western cliff coast leading to Reykjanestá, the most south-western cape of the area.

Geology
The basaltic low relief lava shields of the Reykjanes volcanic system are typically more than 4500 years old, but towards the south there are more recent eruptive fissures, with crater rows, tindars and hyaloclastite hills as well as parts of tuff cones near the south-west shoreline. The offshore volcanoes have produced 15 different tephra layers in the region. The volcano erupted for a 30 odd year period ending in 1240 CE. In 1226 CE an explosive eruption off Reykjanes produced about 0.1 km3 of tephra with deposits up to 100 km away. It also has lava dated to 2150 years ago and 3200 years ago. The Reykjanes volcano has been classified historically with the active as of 2024 Eldvörp–Svartsengi volcano to its south-east as its rift system intersects this to the east in the Reykjanes volcanic belt and the two volcanic systems are very similar, even though they have separate geothermal systems,and lava composition. Recent studies tend to classify the Reykjanes volcanic system as a separate fissure volcano of the Reykjanes volcano belt. This volcanic system marks the transition from the mainly extensional structure of the underwater Reykjanes Ridge of the Atlantic mid-oceanic ridge to a trans-tensional plate boundary in the Reykjanes Peninsula. The 5 - 6 km wide Reykjanes volcanic system is in a rift zone, which extends 45 km, including at least 9 km out to sea towards the Reykjanes Ridge. Volcanic rock production has kept pace with rift extension and subsidence with at least ten eruptions in the 14,500 years since the area became ice free after the end of the last ice age. Within the volcanic system there are active NE–SW dip-slip faults. There are two main fissure swarm zones being in the north (Stampar) and south (Sýrfell). They are separated by about 2 km, and their western parts have been active in the last three eruptive periods of the Reykjanes area.

The volcanic rocks are basalts, with picrite, or tholeiite characteristics. While the active volcanism on the peninsula has been a major source for the geothermal activity in the area, there is evidence that the volcanism can fuel geothermal systems up to 30 kilometers away, as far as Hvalfjörður. On the Reykjanes Peninsula itself, the system has had its geothermal potential exploited, producing up to 176 MW of energy.

Most of the Reykjanes area is at risk of disruption from future eruptions and susceptibility maps have been published.