| Category | Rivers (lava) |
| Continent | Karterus |
| Region | Dhark Bolg |
| Alias | Gald Surtur |
| Map | Tiyaphis |
Surturs Eyebrow is a lava river that crosses much of the Underdark sector Tiyaphis. It has enough rivulets coming off it that some consider it a natural maze. Dead lava tubes, those that no longer have lava in them, are scattered all along the river and in areas. Generally, the main flow flow, or artery is considered Surturs Eyebrow with the side rivulets and tubes being other names or having none at all.
In the Varelay Upheaval (2608 LE - 16 HE), mining by topsiders caused an enormous collapse along the main artery. This culminated in violent volcanic eruptions across Tha'lith. The pressure from the sealed off flow was forced down smaller tubes causing Hen'khas's volcanoes to become very active.
In 16 HE, four centuries after the collapse, lava and pressure finally broke through enough where the volcanoes waned in activity.
Surturs Eyebrow, feeding the volcanoes of Hen'khas's, is also a major trade way for the fiery people of both Dhark Bolg and the surface region above it.
- adamantine from Illadvard, destination Phlem
- spices and vegetables from Phlem, destination Dema'sax
- hardwood from Dema'sax, destination Aebilchunus
- week of relaxation in Aebilchunus's famed steam baths and best whore houses
- summary of a busy merchant trade schedule