The Bosporus is a strait that connects the Black Sea with the Sea of Marmara in
the center of this view of northwest Turkey, taken during the Shuttle Radar
Topography Mission (SRTM). The water of the Black Sea at the top of the image and Sea
of Marmara below the center are colored blue in this image, along with several
large lakes. The largest lake, to the lower right of the Sea of Marmara, is
Iznik Lake. The Bosporus (Turkish Bogazici) Strait is considered to be the
boundary between Europe and Asia, and the large city of Istanbul, Turkey is
located on both sides of the southern end of the strait, visible as a brighter
(light green to white) area on the image due to its stronger reflection of
radar. Istanbul is the modern name for a city with a long history, previously
called Constantinople and Byzantium. It was rebuilt as the capital of the Roman
Empire in 330 A.D. by Constantine on the site of an earlier Greek city, and it
was later the capital of the Byzantine and Ottoman empires until 1922.
The Gulf of Izmit is the narrow gulf extending to the east (right) from the
Sea of Marmara. The city of Izmit at the end of the gulf was heavily damaged by
a large magnitude 7.4 earthquake on August 17, 1999, often called the Izmit
earthquake (also known as the Kocaeli, Turkey, earthquake), that killed at least
17,000 people. A previous earthquake under the Gulf of Izmit in 1754 killed at
least 2,000 people. The Izmit earthquake ruptured a long section of the North
Anatolian Fault system from off the right side of this image continuing under
the Gulf of Izmit. Another strand of the North Anatolian Fault system is visible
as a sharp linear feature in the topography south of Iznik Lake. Bathymetric
surveys show that the North Anatolian Fault system extends beneath and has
formed the Sea of Marmara, in addition to the Gulf of Izmit and Iznik Lake.
Scientists are studying the North Anatolian Fault system to determine the risk
of a large earthquake on the faults close to Istanbul that could kill many more
than the 1999 event.
Three visualization methods were combined to produce this image: shading and
color coding of topographic height and radar image intensity. The shade image
was derived by computing topographic slope in the northwest-southeast direction.
Northwest-facing slopes appear dark and southeast-facing slopes appear bright.
Color coding is directly related to topographic height, with green at the lower
elevations, rising through yellow and brown to white at the highest elevations.
The shade image was combined with the radar intensity image to add detail,
especially in the flat areas.
Size: 2x2 degrees (168 by 222 kilometers; 104 by 138 miles)
Location: 40-42 degrees North latitude, 28-30 degrees East longitude
Orientation: North toward the top
Image Data: shaded and colored SRTM elevation model, with SRTM radar
Original Data Resolution: SRTM 1 arcsecond (about 30 meters or 98 feet)
Date Acquired: February 2000 (SRTM)