Volcanoes in Saudi Arabia

Saudi Arabia has 7 Holocene volcanic fields catalogued by the Smithsonian Global Volcanism Program, all of them basaltic lava fields known in Arabic as 'harrats' — a term meaning rough, stony ground covered by dark lava flows. These harrats form one of the largest continental volcanic provinces on Earth, stretching approximately 2,000 km along the western margin of the Arabian Peninsula from southern Türkiye to Yemen, parallel to the Red Sea rift. The most significant is [[volcano:rahat-harrat|Harrat Rahat]], Saudi Arabia's largest lava field at approximately 20,000 km², which produced the most recent major eruption near the holy city of Medina (Madinah) in 1256 CE.

That event, described in contemporary Islamic historical accounts, sent lava flows to within 12 km of Medina and remains one of the best-documented medieval volcanic eruptions. Saudi Arabia's volcanic heritage is unexpected to many: the kingdom is better known for oil and desert than for volcanism. Yet the harrats collectively cover over 80,000 km² of western Saudi Arabia — an area larger than the Czech Republic — and represent an active volcanic system that has erupted multiple times in the last millennium.

The 2009 seismic swarm beneath Harrat Lunayyir, which included over 30,000 earthquakes and measurable ground uplift, demonstrated that Saudi Arabia's volcanic systems remain restless. The Saudi Geological Survey (SGS) monitors volcanic seismicity across the harrats in cooperation with the King Abdulaziz City for Science and Technology (KACST).

Saudi Arabia's volcanism is directly linked to the Red Sea Rift, one of Earth's youngest and most active continental rift systems. The Arabian Plate is separating from the African (Nubian) Plate at approximately 15–20 mm per year, a process that has been ongoing for roughly 30 million years and has created the Red Sea basin. As the plates diverge, the lithosphere thins along the rift margins, allowing hot asthenospheric mantle to rise and partially melt, producing the basaltic magmas that feed the harrats.

The harrats are concentrated along the western Arabian margin, roughly 100–300 km east of the Red Sea coast, aligned with the rift's shoulder. They represent a form of rift-margin volcanism distinct from the mid-ocean-ridge volcanism developing in the Red Sea's central trough. The dominant rock type across all Saudi harrats is basalt, with some fields (like Khaybar) also producing trachybasalt and evolved felsic compositions.

The volcanic fields are fed by fissure eruptions along NNW–SSE-trending vent systems that parallel the Red Sea rift axis. Harrat Rahat's 300-km length and linear vent distribution exemplify this rift-parallel geometry. The tectonic setting is comparable to the East African Rift volcanic fields in [[country:ethiopia|Ethiopia]] and Kenya, though the Arabian harrats are somewhat older and less active than the most vigorous East African rift centers.

The combined harrat system — extending from the Syrian–Jordanian Harrat Ash Shaam in the north through the Saudi harrats to Yemen in the south — represents one of the largest areas of Cenozoic continental basaltic volcanism on Earth.

**Harrat Rahat** — [[volcano:rahat-harrat|Harrat Rahat]] is Saudi Arabia's largest and most historically significant volcanic field, covering approximately 20,000 km² and extending 300 km south from Medina. A 100-km-long NNW–SSE vent system contains hundreds of basaltic scoria cones, with some evolved trachybasaltic and even trachytic domes in the northern section. Harrat Rahat produced the kingdom's most significant historical eruption in 1256 CE (VEI 3), when lava flows from vents southeast of Medina advanced northwestward for over 23 km, stopping approximately 12 km from the Prophet's Mosque.

The event was documented by multiple Islamic historians and is one of the most detailed medieval eruption accounts from anywhere in the world. An earlier eruption around 641 CE is also recorded. With approximately 3 eruptions in the Holocene database and a VEI max of 3, Harrat Rahat is the most hazardous volcanic system in Saudi Arabia.

**Harrat Khaybar** — [[volcano:khaybar-harrat|Harrat Khaybar]] covers more than 14,000 km² north of Medina and is one of the largest volcanic fields in the Arabian Peninsula. Its 100-km NNS vent system includes the Jabal Qidr stratovolcano, felsic lava domes, and tuff rings alongside the dominant basaltic cones. At least 7 lava flows are less than 4,500 years old, and 8 more are less than 1,500 years old.

A confirmed eruption around 650 CE (VEI 2) produced extensive lava flows. Khaybar's distinctive 'white volcano' (Jabal Abyad) and 'black-and-white volcano' are among the most photogenic volcanic landmarks in Saudi Arabia.

**Harrat Lunayyir** — [[volcano:lunayyir-harrat|Harrat Lunayyir]] is one of the smallest Saudi harrats but gained international attention in April–June 2009 when a seismic swarm of over 30,000 earthquakes (the largest M 5.7) and 40 cm of ground uplift occurred beneath the field. The event was interpreted as a shallow dike intrusion that nearly reached the surface — the closest Saudi Arabia has come to a volcanic eruption in modern times. Approximately 40,000 people were evacuated from nearby villages.

One confirmed eruption around 1000 CE is recorded. The 2009 event significantly upgraded Saudi Arabia's volcanic monitoring program.

**Jabal Yar** — Jabal Yar (305 m / 1,001 ft) in the southern Asir region produced Saudi Arabia's most recent confirmed eruption in 1810 (VEI 2). It is the lowest-elevation and southernmost of the Saudi harrats.

**Harrat Kishb** — Harrat Kishb (1,475 m / 4,839 ft) lies east of Mecca and covers approximately 6,000 km². It has no confirmed historical eruptions but contains young-appearing lava flows.

**Harrat Ithnayn** — Harrat Ithnayn (1,625 m / 5,331 ft) in the north has no confirmed eruptions but represents the northernmost Saudi harrat.

**Harrat al Birk** — Harrat al Birk (587 m / 1,926 ft) in the southern Asir coastal zone has no confirmed Holocene eruptions.

Saudi Arabia's eruption record is short but significant, with 6 catalogued eruptions across the 7 harrats. The most consequential event was the 1256 CE eruption of Harrat Rahat, one of the most thoroughly documented medieval volcanic eruptions in the world. Islamic historians including Abu Shama and Ibn al-Athir described the eruption in detail: lava flows began from vents southeast of Medina and advanced toward the holy city for several weeks, creating panic among the population.

The flows traveled over 23 km before halting approximately 12 km from the Prophet's Mosque, an event interpreted at the time as divine intervention. The eruption was assigned VEI 3 and produced a lava field clearly visible today. Harrat Rahat also records an earlier eruption around 641 CE (VEI 2), and an uncertain event in 1292.

Harrat Khaybar produced a VEI 2 eruption around 650 CE. Jabal Yar's 1810 eruption (VEI 2) in the far south was the kingdom's most recent confirmed event. Harrat Lunayyir's eruption around 1000 CE is the only confirmed event for that field.

The 2009 Lunayyir seismic swarm — though it did not result in eruption — was the most significant volcanic unrest event in modern Saudi Arabian history, demonstrating that the harrats remain capable of producing eruptions with little long-term warning.

Saudi Arabia's volcanic hazards center on the potential for basaltic fissure eruptions from the harrats, particularly Harrat Rahat due to its proximity to Medina (population ~1.5 million) and Mecca (population ~2 million). A repeat of the 1256 eruption could send lava flows toward Medina's expanding urban area, which has grown significantly closer to the volcanic field since the 13th century. Basaltic fissure eruptions produce fast-moving lava flows (potentially 10+ km/hr on steep terrain), volcanic gases, and localized tephra fall.

While fatalities from lava flows are rare due to their visibility and the ability to evacuate, infrastructure damage would be enormous. The 2009 Lunayyir seismic swarm demonstrated an additional hazard: the seismicity itself caused building damage, ground cracking, and mass panic, requiring evacuation of ~40,000 people — even without an eruption. If the 2009 dike intrusion had reached the surface, it would have produced a Strombolian to Hawaiian-style eruption with lava fountaining and flows.

The Saudi Geological Survey has significantly expanded its volcanic monitoring network since 2009, deploying seismometers, GPS stations, and InSAR satellite monitoring across the major harrats. A volcanic hazard assessment for Harrat Rahat was published in cooperation with the USGS, and eruption contingency planning for Medina has been developed.

Saudi Arabia's 7 Holocene volcanic fields form a roughly linear belt parallel to the Red Sea, extending approximately 1,500 km from north to south along the western margin of the Arabian Peninsula. From north to south: Harrat Ithnayn (26.6°N) in the northern desert; Harrat Khaybar (25.5°N) and Harrat Lunayyir (25.2°N) north of Medina; Harrat Rahat (23.1°N) stretching 300 km south from Medina; Harrat Kishb (22.8°N) east of Mecca; Harrat al Birk (18.4°N) on the Asir coastal plain; and Jabal Yar (17.1°N) in the far south near the Yemen border. The fields are concentrated 100–300 km east of the Red Sea coast, aligned along the rift shoulder.

Harrat Rahat and Harrat Khaybar are the two largest, together covering over 34,000 km². The cross-border Harrat Ash Shaam, shared with Syria and Jordan, extends the volcanic belt northward into the Levant. The entire Saudi harrat system sits on thick continental crust (>25 km) of the Arabian Shield.

Saudi Arabia's volcanic fields have shaped both the physical landscape and the cultural history of the Arabian Peninsula. The 1256 Harrat Rahat eruption near Medina is recorded in Islamic historical literature and holds religious significance — the event was interpreted as one of the signs prophesied by the Prophet Muhammad. The lava field from that eruption is still clearly visible south of Medina and has influenced urban planning as the city expanded.

The harrats' dark basaltic landscapes contrast dramatically with the surrounding pale desert, creating striking visual features visible from space. Harrat Khaybar's unusual volcanic landforms — including the 'white volcano' Jabal Abyad and the distinctive lava formations — have attracted growing geological tourism interest, particularly as Saudi Arabia develops its tourism sector under Vision 2030. The harrats have historically been barriers to travel and settlement, with their rough lava surfaces impassable to traditional caravans — the Arabic word 'harrat' itself reflects this harsh terrain.

Archaeologically, the volcanic fields contain extensive pre-Islamic rock art and stone structures, preserved by the hostile terrain that discouraged later settlement.

Saudi Arabia's volcanic fields are increasingly accessible as the kingdom develops tourism infrastructure under Vision 2030. Harrat Khaybar, with its dramatic volcanic cones and the photogenic Jabal Abyad ('White Mountain'), is emerging as a geological tourism destination approximately 130 km north of Medina. The AlUla region, though primarily known for the Nabataean archaeological site of Hegra (Mada'in Salih), sits adjacent to volcanic terrain.

Harrat Rahat's 1256 lava field south of Medina can be viewed from highway vantage points. The Hejaz Railway runs through volcanic landscapes. Access to the more remote harrats (Lunayyir, Kishb, Ithnayn) requires 4WD vehicles and is currently limited to geological expeditions.

Saudi Arabia's volcanic sites lack the developed visitor infrastructure found at volcanic parks in [[country:spain|Spain]] or [[country:iceland|Iceland]], but this is expected to change as the country's tourism sector grows.