Transmitters from the telephone company Sími and Icelandic National Television RÚV occupy the site where the U.S. Navy had installed radar stations.

The mountain is near the tip of Reykjanes peninsula between Svartsengi Power Station with the Blue Lagoon and the town of Grindavík at road 43 to the east.

A visible tectonic graben[6] runs over the top of the mountain[7] forming a small canyon, up to 80 m deep.

Analysis of aerial photographs of shield volcanoes and glaciovolcanic edifices makes clear that the latter have much steeper slopes.

[10] It also built up a meltwater lake that Pedersen et al. define as “a pillow-dominated flat-topped tuya without a lava cap”.

[7] H. Björnsson explains that though the mountain is crossed by many faults and a graben, so that it looks like a complex formation, its origin is in a single eruption.

[6] In the upper part of Þorbjörn, there is also a rather eroded crater but, probably because of the erosion, no trace of subaerial lavas has been found.

[6] The tuya is slightly elongated in the direction of the volcanic fissure systems of Reykjanes, i.e. southwest to northeast.

[11] As is often the case on Reykjanes peninsula, swarms of small earthquakes and associated ground uplift, thought to be linked to magma intrusions, began in the region in 2020, and again in 2023.

At the same time, uplift was about 10 cm (3.9 in) around Þorbjörn caused by a magmatic intrusion, a sill, at a depth of 3–4 km (1.9–2.5 mi).