Sunday, December 6, 2009

New Oblique Satellite Images of Ramon's Crater, HaMakhtesh Hagadol, and HaMakhtesh HaKatan

Links of interest:

Safed Earthquakes

Bing oblique satellite images of Mitzpe Ramon

Bing oblique satellite images of Israel's most prominent geological features

Microsoft's Bing has come out with some new oblique satellite images of the Negev that surpass anything I have seen before. An oblique image is taken at an angle so as to enhance the contrast of topological features. Some of the new features shown are HaMakhtesh Hagadol (The Large Crater) and HaMakhtesh HaKatan (The Small Crater), each considerably smaller than Makhtesh Ramon, on whose rim Mitzpe Ramon sits. At the time of its charting Makhtesh Ramon was unknown, hence the name "The Large Crater" for Makhtesh Ramon's smaller brother. These are three of five such erosion craters in Israel, with only seven existing in the entire world. The Large and Small Crater are seen to the north east of Mitzpe Ramon and Ramon's Crater, the Small Crater lying near Highway 25, just west of the southern Dead Sea., and the Large Crater lying near Yeroham. They are easily seen in this high relief, oblique satellite image.

Makhtesh Ramon (Center, Orange marker); HaMakhtesh Hagadol and HamAkhtesh Hakatan (North East); Wadi al Jayb (Jordan Rift Valley)

Another wonderful geological feature, seen above, that is hard to see on maps is the Jordan Rift Valley, a continuation of the Great African Rift Valley that begins at Mt. Kilimanjaro in norther Tanzania, continues northward under the Gulf of Aqaba, through the Dead Sea and the Jordan River Valley, culminating in the Beqa'a Valley of Syria. This great trench, running nearly 5,000 miles, is formed by three tectonic plates that meet and pulll apart under the Gulf of Aqaba. This geologically active trench is responsible for generating Mt. Kilimanjaro itself as well as the earthquake of Jan. 1, 1837 which completely destroyed Safed.  The Jordan Rift Valley is marked on our map as "Wadi al Jayb", continuing up to and under the Dead Sea, and whose depth and extent is magnificently highlighted in the above oblique satellite image.

Geological features dominate the political geography of the Middle East. From the bottom: drying ponds of the Dead Sea, Dead Sea, Jordan River Valley, Sea of Galilee, Golan Heights (to the immediate right), Lebanon Mts. and Beqaa Valley veering off to the top right, all continuations of the 5,000 mile long Great African Rift Valley. Note also the prominent Negev border with Egypt which I cannot attribute to any geological feature.

Below, in this gorgeous satellite mosaic of a cloudless Africa and Middle East, we see the telltale markings of the Great African Rift Valley, running from Mt. Kilimanjaro (red marker), due north through Israel (blue marker), forming the Jordan Rift Valley, Dead Sea, Jordan River Valley, and the Beqa'a Valley in Syria.

While here take some time to enjoy the breath taking image of Lake Victoria, the Nile River and Delta (the verdant delta of the river being seen here quite literally). This is the first time I have ever seen evidence of the boundary between Israel and Egypt on a satellite image. If you look closely at the Negev's boundary with Egypt, you can see the triangular shape of the Negev's border clearly delineated on the map. I have no idea what causes this feature.

Great African Rift Valley, Lake Victoria, Nile River and Delta, Jordan Rift Valley, Dead Sea, & Jordan River Valley

Cloudless satellite images of such extent are difficult to prepare. They consist of thousands of tiled mosaic images of an area, each one taken when no clouds were present. This is the way the earth usually looks from space:

The cloudy third planet from the Sun

Large scale cloudless satellite mosaics were pioneered by Tom van Sant in the late '80s, and his satellite mosaic maps of a cloudless earth are some of the best known. I once had the privilege of interviewing Tom van Sant when he was a guest lecturer at the University of California, Berkeley, and I was the project manager for Project Sequoia 2000.

 Tom van Sant's original cloudless Earth, from thousands of satellite mosaic images

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