Volcanoes in Cameroon

Cameroon has 3 Holocene volcanoes recorded in the Smithsonian Global Volcanism Program database, all lying along the Cameroon Volcanic Line (CVL), one of Africa's most distinctive geological features. The country's volcanic centerpiece is [[volcano:cameroon|Mount Cameroon]] — at 4,095 m (13,435 ft), it is the highest peak in West Africa and the region's most active volcano, with 19 recorded eruptions dating back to the 5th century BCE. The massive basaltic-to-trachybasaltic edifice rises directly from the coast of the Gulf of Guinea, making it one of the largest volcanic structures in Africa by volume (approximately 1,400 km³).

The [[volcano:tombel-graben|Tombel Graben]] volcanic field lies between Mount Cameroon and Mount Manengouba, containing young cinder cones and maars at lower elevation. Perhaps most internationally known, however, is the [[volcano:oku-volcanic-field|Oku Volcanic Field]] in the highlands of northwest Cameroon, which contains Lake Nyos — the site of the catastrophic carbon dioxide gas release on August 21, 1986, that killed at least 1,700 people in one of the [[ranking:deadliest-eruptions|deadliest volcanic disasters]] of the 20th century. Together, Cameroon's volcanic systems illustrate two very different volcanic hazards: the conventional threat of lava flows and explosive eruptions at Mount Cameroon, and the insidious danger of lethal volcanic gas accumulation in crater lakes.

The Cameroon Volcanic Line continues offshore into the Gulf of Guinea, where the islands of São Tomé and Príncipe, Bioko (Equatorial Guinea), and Annobón are also volcanic.

Cameroon's volcanism is concentrated along the Cameroon Volcanic Line (CVL), a roughly 1,600 km (990 mi) chain of volcanic centers extending from the Gulf of Guinea islands northeastward through Mount Cameroon and into the continental interior. The CVL is a geological enigma: unlike most volcanic chains, it does not sit on a plate boundary and does not show the age progression characteristic of a classical hotspot track like Hawaii. Instead, the CVL is thought to result from a combination of deep mantle upwelling (possibly related to a thermal anomaly at the boundary of the African Large Low Shear Velocity Province), reactivation of ancient Precambrian fault systems, and localized lithospheric thinning.

The continental crust beneath the CVL exceeds 25 km in thickness, classifying all Cameroonian volcanism as intraplate / continental. The CVL's volcanic rocks range from basalt to phonolite and trachyte, with Mount Cameroon producing predominantly basaltic to trachybasaltic lavas. The volcanic line's orientation follows ancient structural weaknesses in the African craton, suggesting that pre-existing tectonic architecture plays a key role in focusing magmatic activity.

Cameroon is not part of the [[special:ring-of-fire|Ring of Fire]] or the East African Rift System; its volcanism represents an independent, intraplate magmatic province.

**Mount Cameroon** — West Africa's most active volcano and highest peak, [[volcano:cameroon|Mount Cameroon]] (known locally as Mongo ma Ndemi, meaning 'Mountain of Greatness') is a massive steep-sided [[special:types-of-volcanoes|stratovolcano]] that rises from sea level to 4,095 m (13,435 ft) over a distance of just 25 km, creating one of the steepest elevation gradients of any volcano on Earth. The edifice has a volume of approximately 1,400 km³ and more than 100 satellitic cinder cones on its flanks and surrounding lowlands. The Smithsonian database records 19 eruptions from approximately 450 BCE to 2000 CE, with particularly frequent activity from the 19th century onward.

Notable historical eruptions include the 1922 southwest-flank eruption that sent a lava flow to the Atlantic coast, the 1999 south-flank eruption whose lava stopped only 200 m from the sea, and the 2000 upper southeast-flank eruption. The Carthaginian navigator Hanno may have described an eruption of Mount Cameroon during a voyage along the West African coast in the 5th century BCE, making it one of the earliest recorded volcanic observations outside the Mediterranean. The mountain hosts the annual Mount Cameroon Race of Hope, where runners ascend and descend the volcano in a single day.

Eruption VEI values have ranged from 1 to 3.

**Tombel Graben** — The [[volcano:tombel-graben|Tombel Graben]] (also called the Tombel Plain) is a low-lying volcanic field between Mount Cameroon and Mount Manengouba, containing young cinder cones and maars. The field reaches only 500 m (1,640 ft) in elevation and lies within the graben structure at approximately 4°58'N, 9°51'E. No Holocene eruptions have been confirmed, but the presence of young-looking volcanic features suggests activity within the last 10,000 years.

The Tombel Graben rocks are trachybasaltic to basanitic in composition, consistent with the broader Cameroon Volcanic Line chemistry.

**Oku Volcanic Field** — The [[volcano:oku-volcanic-field|Oku Volcanic Field]] in northwest Cameroon's highlands contains numerous maars and basaltic cinder cones on and near the deeply dissected Mount Oku massif, which reaches 3,011 m (9,879 ft). The field is best known for two crater lakes that have produced catastrophic carbon dioxide gas release events. On August 15, 1984, Lake Monoun released CO2 that killed 37 people — attributed to overturn of stratified lake water triggered by an earthquake and landslide.

Far more devastating was the Lake Nyos disaster on August 21, 1986, when approximately 1 km³ of magmatic CO2 was released from the lake, flowing downhill as a heavy, invisible cloud and suffocating at least 1,700 people and thousands of livestock in surrounding valleys. The Lake Nyos disaster was one of the deadliest volcanic events of the 20th century and prompted worldwide scientific study of volcanic lake hazards. Degassing systems have since been installed in both lakes to gradually reduce dissolved CO2 concentrations.

Cameroon's eruption history is dominated by Mount Cameroon, whose 19 documented eruptions make it by far the most frequently active volcano in West Africa. The earliest recorded eruption, around 450 BCE, may correspond to the account of Carthaginian navigator Hanno, who described a fiery mountain on the West African coast during a voyage of exploration. After a gap in the historical record, eruptions were documented in approximately 1650 CE (VEI 3) and 1807 (VEI 3).

From the 19th century onward, the record becomes increasingly detailed: eruptions occurred in 1825, 1838, 1852, 1865, 1866, 1868, 1871, 1909, 1922, 1925, 1954, 1959, 1982, 1989, 1999, and 2000. Most eruptions have produced effusive basaltic lava flows from flank fissures, with [[special:volcanic-explosivity-index|VEI]] values typically ranging from 1 to 3. The 1922 eruption is particularly notable: lava from a southwest-flank fissure reached the Atlantic Ocean.

The 1999 eruption produced lava flows that advanced rapidly down the south flank, stopping just 200 m from the coast and destroying farmland. The 2000 eruption, from two vents on the upper southeast flank, was the most recent confirmed activity. The Oku Volcanic Field has 2 recorded events, both uncertain: a possible eruption at Lake Nyos around 1550 CE (VEI 3), and the 1986 gas release event.

The 1986 Lake Nyos disaster, while not a conventional eruption, released approximately 1 km³ of volcanically derived CO2, killing at least 1,700 people.

Cameroon faces two distinct categories of volcanic hazards. Mount Cameroon presents conventional volcanic risks: lava flows, tephra fall, volcanic gas emissions, and potentially lahars. The city of Buea (population ~90,000), the capital of the Southwest Region, sits directly on the lower southeastern flank of the volcano at approximately 1,000 m elevation.

The port city of Limbe lies near the southwestern base. Eruptions in 1999 and 2000 demonstrated that lava flows can reach populated areas and agricultural zones rapidly. However, Mount Cameroon's primarily basaltic eruptions tend to produce relatively predictable lava flows rather than explosive pyroclastic events, giving populations some warning time.

The far more insidious hazard lies in the crater lakes of the Oku Volcanic Field. The 1986 Lake Nyos disaster demonstrated that volcanic CO2 can accumulate in stratified crater lakes and be released catastrophically, creating invisible, ground-hugging clouds of asphyxiating gas. Following the disaster, international teams installed degassing systems in both Lake Nyos and Lake Monoun, which use pipes to continuously siphon CO2-rich deep water to the surface for controlled release.

These systems have significantly reduced the risk but require ongoing maintenance. The Lake Nyos disaster prompted establishment of the UNEP-supported Lake Nyos Degassing Project and catalyzed global research into volcanic lake hazards, including studies of [[country:dr-congo|Lake Kivu in DR Congo]].

Cameroon's three volcanic systems span the country's southwestern and northwestern regions along the Cameroon Volcanic Line. Mount Cameroon dominates the southwest, rising from the Gulf of Guinea coast near the city of Limbe at approximately 4°12'N latitude. The Tombel Graben lies northeast of Mount Cameroon in a lowland between the major volcanic massifs.

The Oku Volcanic Field is located further northeast in the highland region around 6°15'N, at significantly higher base elevation. The Cameroon Volcanic Line extends both to the southwest (offshore to Bioko, São Tomé) and northeast (toward the Adamawa Plateau and into Chad), but only the three Holocene-active systems within Cameroon proper are cataloged.

Mount Cameroon is central to the cultural identity of the Bakweri and other peoples of the southwestern region. The annual Mount Cameroon Race of Hope, held since 1973, is one of Africa's most prestigious mountain races, attracting runners who ascend and descend the 4,095 m peak in a single day (the fastest in under 4.5 hours). The volcano's fertile lower slopes support extensive plantations of cocoa, tea, bananas, and oil palm — crops that form the backbone of the regional economy.

The Cameroon Development Corporation (CDC), one of the country's largest employers, operates plantations on the volcanic soils around Limbe and Buea. The Lake Nyos disaster of 1986 had a profound impact on Cameroonian society and international volcanology: it prompted mass evacuation of surrounding villages (some still uninhabited decades later), established new protocols for monitoring volcanic lakes worldwide, and led to the installation of CO2 degassing systems that have become models for similar hazard management globally.

Mount Cameroon is increasingly popular with trekkers and is Cameroon's premier adventure tourism destination. The standard two-day ascent begins from Buea, with overnight stays at mountain huts at approximately 2,800 m and 3,800 m. The summit at 4,095 m offers views across the Gulf of Guinea and, on clear days, as far as the islands of Bioko and São Tomé.

Treks are arranged through the Mount Cameroon Ecotourism Organisation and local guides are required. The best trekking season is November to February during the dry season; the mountain receives some of the highest rainfall in Africa during the wet season (up to 10,000 mm annually on its southwestern slopes). Lake Nyos, while accessible by road, is primarily of scientific interest and sobering historical significance.

Visitors can view the degassing pipes and the haunting, still-turquoise lake that claimed so many lives in 1986.