Jordan Rift Valley

The Jordan Rift Valley, also Jordan Valley ( ''Bīqʿāt haYardēn'', Al-Ghor or Al-Ghawr), is an elongated endorheic basin located in modern-day Israel, Jordan and the West Bank, Palestine. This geographic region includes the entire length of the Jordan River – from its sources, through the Hula Valley, the Korazim block, the Sea of Galilee, the (Lower) Jordan Valley, all the way to the Dead Sea, the lowest land elevation on Earth – and then continues through the Arabah depression, the Gulf of Aqaba whose shorelines it incorporates, until finally reaching the Red Sea proper at the Straits of Tiran.

History and physical features

The Jordan Rift Valley was formed many millions of years ago in the Miocene epoch (23.8 – 5.3 Myr ago) when the Arabian plate moved northward and then eastward away from Africa. One million years later, the land between the Mediterranean and the Jordan Rift Valley rose so that the sea water stopped flooding the area. Alternatively, it was a fall in the sea level that caused the disconnection, or a mix between the two phenomena – researchers have not yet reached a consensus.

The geological and environmental evolution of the valley since its inception in the Oligocene can be seen in a variety of sedimentary and magmatic rock units, preserved as continuous sequences in the deeper basins. The outcropping formations around the basins represent alternating deposition and erosion phases.

The lowest point in the Jordan Rift Valley is in the Dead Sea, the lowest spot of which is below sea level. The shore of the Dead Sea is the lowest dry land spot on Earth, at below sea level. With its flanks rising sharply to almost above sea level in the west, and similarly in the east, the rift is a significant topographic feature over which a few narrow paved roads and difficult mountain tracks lead. The valley north of the Dead Sea has long been a site of agriculture because of water available from the Jordan River and numerous springs located on the valley's flanks.

Dead Sea Transform

The plate boundary that extends through the valley is variously called the Dead Sea Transform (DST) or Dead Sea Rift. The boundary separates the Arabian plate from the African plate, connecting the divergent plate boundary in the Red Sea (the Red Sea Rift) to the East Anatolian Fault in Turkey.

The DST fault system is generally considered to be a transform fault that has accommodated a northwards displacement of the Arabian plate. This interpretation is based on observation of offset markers, such as river terraces, gullies and archaeological features, giving horizontal slip rates of several mm per year over the last few million years. GPS data give similar rates of present-day movement of the Arabian plate relative to the Africa plate. It has also been proposed that the fault zone is a rift system that is an incipient oceanic spreading center, the northern extension of the Red Sea Rift.

In 1033, the rift valley was struck by a magnitude 7.3 earthquake, believed to have been produced along the DST fault system. It caused widespread destruction, a tsunami, and killed 70,000 people.

Seismic risk

The 1033 AD event was the last large earthquake on the Jordan Valley Fault. Given the estimated slip rate is per year, approximately of potential slip has been accumulated. An estimated of slip could be produced during a future earthquake along a × fault area. Such an event would suggest an earthquake of 7.4, posing a great seismic threat to the region.

In late 2020, researchers at Tel Aviv University said that an earthquake of magnitude 6.5 is expected to occur in the area, resulting in many fatalities. Researchers also stated that the frequency of large earthquakes in the region is significantly underestimated. Previous studies suggested a recurrence interval of 10,000 years for magnitude 7.5 earthquakes, but the researchers said the figure was 1,300 to 1,400 years. Yosef Shapira, the then State Comptroller of Israel, said that a major earthquake in Israel could kill up to 7,000 people if safety recommendations are not enforced. Reports of the years 2001, 2004 and 2011 found that the Israeli government did not fund any retrofitting works to old construction. Although the government said in 2008 that it would retrofit hospitals and schools, no major changes were made.

Climate

See also

* Geography of Israel
* Geography of Jordan
* Great Rift Valley

References

External links

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Valleys of Asia
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Cenozoic geology of Asia
Cenozoic rifts and grabens
Dead Sea
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Geography of Palestine (region)
Landforms of Jordan
Valleys of the West Bank
Levant
Regions of Israel
Regions of Palestine
Rifts and grabens
Valleys of Israel
Depressions of Israel
Depressions of Jordan