50 Fun Facts About Great Rift Valley

Roughly how long is the Great Rift Valley, from northern Syria to Mozambique?

Geologists now prefer the term Afro-Arabian Rift System for the structures beneath it.

Which British geologist introduced the term Great Rift Valley in 1896?

He built on Austrian geologist Eduard Suess's idea of a linked set of features from Syria to Mozambique; the eastern branch is named after him.

Gregory defined a rift valley as a linear valley with steep, almost vertical sides that has done what?

He visited central Kenya in 1893 and 1919; his 1896 book The Great Rift Valley is a classic.

The East African Rift is a boundary where the African plate is splitting in two. What are the two halves called?

Three microplates, Victoria, Rovuma and Lwandle, sit within the system.

At what rate are the two sides of the East African Rift pulling apart?

Marine geologist Kathleen Crane suggests eastern Africa could eventually separate from the mainland, but over tens of millions of years.

The East African Rift began developing at the onset of which geological epoch, 22-25 million years ago?

Enormous continental flood basalts had erupted first, lifting the Ethiopian, Somali and East African plateaus.

Where do the Red Sea Rift, the Aden Ridge and the East African Rift meet?

The depression beside it is a zone of thinned, heavily intruded crust and the hottest year-round place on Earth.

South of Ethiopia the system splits into an eastern branch and a western branch. What are they called?

They pass either side of the Victoria microplate and rejoin north of Lake Malawi.

The northern, Asian section of the Great Rift Valley is formed by which plate boundary?

It runs from southeastern Turkey to the Gulf of Aqaba, with pull-apart basins that hold the Dead Sea and Sea of Galilee.

The most northerly part of the Great Rift Valley is a plain along which river in Syria?

The Ghab Plain lies above the Ghab basin; the Beqaa valley comes next to the south.

The Dead Sea's shores are the lowest land on Earth, roughly how far below sea level as of 2025?

Its water is about 34% salt.

The Dead Sea is roughly how many times saltier than the ocean?

The salinity was measured at 342 grams per kilogram in 2011; nothing much can live in it, hence the name.

During the Pleistocene the whole Dead Sea depression was filled by which vanished body of water?

Even at its highest, its surface was still about 200 metres below sea level.

The section of the rift between the Dead Sea and the Gulf of Aqaba is known as what?

Its northern part is also called the Arava valley; the watershed sits at about 200 metres.

The Danakil Depression, first African section of the rift south of the Red Sea, lies roughly how far below sea level?

It sits between the Ethiopian Plateau and the Danakil Alps and forms the northern tip of the Afar rift.

Dallol in the Danakil Depression holds what climatic record?

Daily means there ranged from 30 °C in January to 39 °C in July in the 1960s.

Erta Ale in Ethiopia's Afar region is famous for what?

Only about eight volcanoes worldwide had lava lakes in 2019.

Ol Doinyo Lengai in Tanzania is the world's only active volcano erupting which unusual lava?

The magma is almost silica-free and flows like olive oil; it erupts dark and turns white like snow within days.

What do the Maasai call Ol Doinyo Lengai?

Legend says the god Engai withdrew there after being hit by a hunter's arrow.

Mount Kilimanjaro, on the rift shoulder in Tanzania, is how tall?

It is Africa's highest mountain and the world's highest free-standing mountain; Hans Meyer first reached the top in 1889.

Kilimanjaro's two named peaks, Kibo and Mawenzi, have names meaning what?

Kibo is spotted with snow; Mawenzi has a jagged summit.

Which lake in the western branch is the world's longest freshwater lake and second deepest after Baikal?

Burton and Speke were the first Westerners to reach it, in 1858.

Lake Malawi is home to more species of fish than any other lake, including at least how many cichlid species?

David Livingstone reached it in 1859 and named it Lake Nyasa; it is 706 metres deep at its deepest point.

Lake Victoria, though not itself in a rift trough, is Africa's largest by area and the world's largest of what kind?

John Hanning Speke named it after Queen Victoria in 1858; it is second only to Lake Superior among freshwater lakes by area.

Which invasive fish has driven many of Lake Victoria's endemic species to extinction?

The lake occupies a shallow depression and has dried to smaller lakes at times in its history.

The Jade Sea in northern Kenya holds which two world records?

Its turquoise colour earned it the nickname the Jade Sea.

The Jade Sea was named Lake Rudolf in 1888 by which Hungarian explorer, in honour of Austria's crown prince?

His second-in-command, the Austrian Ludwig Ritter von Höhnel, accompanied him.

Lake Natron's water can reach a pH above 12 and does what to the bodies of animals that die in it?

Halophilic microbes turn its salt crust red and pink.

Lake Natron is the only regular East African breeding site for how many lesser flamingos?

Their "near threatened" status stems from dependence on this single site; they feed on red-pigmented Spirulina.

Lake Kivu is one of only three lakes in the world known to undergo what kind of catastrophic event?

Dissolved carbon dioxide and methane in its depths could threaten two million people if the lake overturns.

Olduvai Gorge, the famous fossil ravine, is roughly how long?

It lies in the eastern Serengeti Plains, about 45 km from Laetoli, another key hominin site.

Which husband-and-wife team established the excavations at Olduvai Gorge?

Mary found the Zinjanthropus skull at the FLK site in July 1959.

The skull Mary Leakey found at Olduvai in 1959 belonged to which species?

The FLK site was named for Frida Leakey plus korongo, Swahili for gully.

The stone tool industry Louis Leakey first described in 1951, named after the gorge, is called what?

Choppers made up over half the tools found; the Leakeys identified 11 Oldowan sites in the gorge.

Which German geologist made the first European study of Olduvai's strata in 1913, hauling mammal fossils back to Berlin?

Louis Leakey saw the collection in Berlin in 1928 and realised some pieces were artefacts.

The 3.2-million-year-old skeleton Lucy was found in 1974 at Hadar, in which region of the rift?

Donald Johanson found 40% of the Australopithecus afarensis skeleton; she was named after a Beatles song played in camp.

The 1974 Hadar skeleton was nicknamed after a Beatles song played repeatedly in the expedition camp. Which song?

Pamela Alderman suggested the name; Ethiopians call her Dinkinesh, "you are marvellous".

The Ngorongoro Crater takes its name from what?

The huge caldera in Tanzania's Crater Highlands is a UNESCO World Heritage Site.

Which Scottish explorer, on an 1879-80 Royal Geographical Society expedition, first deduced the existence of a great fault in East Africa?

In 1883 he travelled the Kenyan valley from Mount Longonot to Lake Baringo, describing a trough twenty miles broad with mountains rising 9,000 feet.

What is the maximum depth of the Red Sea's narrow central valley, which links the Asian and African sections of the rift?

Its central valley is less than 60 km wide with broad shallow flanks.

The East African Rift is the largest seismically active rift system on Earth. Where do most of its earthquakes occur?

Earthquakes in the past century reached about magnitude 7.0, with shallow foci of 12-15 km under the rift axis.

Which two ancient, stable blocks of crust are named in the East African Rift article?

Cratons are thick, billions of years old and rich in gold, chromium and nickel.

Besides the East African system, which two other continental rifts are considered active?

A fourth, the West Antarctic Rift System, may also be active.

Which feature on Mars is believed to be a giant rift system 4,000 km long?

On Earth, Baikal in Siberia sits in an active rift and holds 20% of the world's liquid fresh water.

Which Kenyan rift lake, protected by a national park, once formed one deep freshwater body with Elementaita and Bogoria?

It sits at 1,754 metres and has nearly dried up several times in the past 50 years.

The rift's western branch is dominated by a series of deep lakes. Which one of them alone is endorheic and alkaline?

The western branch has very little volcanic rock compared with the eastern branch.

In Tanzania the eastern rift spreads out into rift structures toward Lake Eyasi, Lake Manyara and the Pangani basin. What is this zone called?

Large volcanoes such as Mount Kenya and Kilimanjaro sit on the rift shoulders, not on its floor.

The Gregory Rift's shoulders rise how far above the inner graben?

The shoulders stand over 3,000 metres above sea level; the rift is widest in the Afar and narrows to a few km in northern Tanzania.

Volcanism and rifting in Kenya began 40-35 million years ago in which northern region, home to the Jade Sea?

It then spread north and south, reaching central Kenya about 15 million years ago and northern Tanzania about 8 million years ago.

The Ethiopian section of the rift climbs to what elevation on the valley floor in its central part?

From the Afar Depression the floor rises continuously before descending into the "broadly rifted zone".