Fault Responsible for Haiti Quake Slices Island’s Topography
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A magnitude 7.0 earthquake occurred on January 12, 2010, at Port-au-Prince, Haiti, with major impact to the region and its citizens. This perspective view of the pre-quake topography of the area clearly shows the fault that is apparently responsible for the earthquake as a prominent linear landform immediately adjacent to the city. Elevation is color coded from dark green at low elevations to white at high elevations, and the topography is shaded with illumination from the left. The topography in this image is exaggerated by a factor of two. The sharp diagonal line exactly at the image center is the Enriquillo fault. Port-au-Prince is immediately to the left (north) at the mountain front and shoreline. View Width: One degree latitude (111 kilometers, or 69 miles); View Distance: Five degrees longitude (525 kilometers, or 325 miles); Location: 18 to 19 degrees North latitude, 70 to 75 degrees West longitude; Orientation: View east, 5 degrees below horizontal; SRTM Data Acquired: February 2000 Courtesy of NASA/JPL/NGA |
The fault responsible for the January 12, 2010, magnitude 7.0 earthquake that devastated Haiti is visible in images created using NASA radar topography data acquired in 2000. This perspective view of the pre-earthquake topography of the area was created using data from the Shuttle Radar Topography Mission that flew aboard Space Shuttle Endeavour in February 2000. It clearly shows the Enriquillo fault that is apparently responsible for the earthquake.
The fault is visible as a prominent linear landform that forms a sharp diagonal line at the center of the image. The Enriquillo fault generally moves left-laterally (horizontally, with features across the fault shifting to the left when the fault breaks in an earthquake), but vertical movements occur along the fault where irregularities in the fault line cause local compression or extension of the earth. Meanwhile, movements of the topography at the Earth’s surface can falsely appear to be vertical where mountain slopes are cut and misaligned by horizontal shifts of the fault.
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Haiti (on the west) and the Dominican Republic (on the east) share the island of Hispaniola. Port-au-Prince is located at the east end of the northern shore of Haiti’s southern peninsula. This view of the topography of the island shows the fault as a prominent linear landform immediately southwest of the city and as a series of fault traces that extend westward along the full length of the southern peninsula. View Area: 388 by 735 kilometers (240 by 455 miles); Location: 19 degrees North latitude, 71 degrees West longitude; Orientation: North to the top; SRTM Data Acquired: February 2000 Courtesy of NASA/JPL/NGA |
Additionally, differing erosion rates on the two sides of the fault, due to the juxtapositioning of differing rock types by the fault, can give the appearance of vertical offsets of the current topographic surface. All of these real and apparent horizontal and vertical offsets of the topographic surface may (and likely do) occur here, making the fault easily observed in the topographic data.
SRTM acquired elevation measurements for nearly all of Earth’s landmass between 60 degrees North and 56 degrees South latitudes. For many areas of the world, SRTM data provide the first detailed three dimensional observation of landforms at regional scales.
The mission was a cooperative project between
• the National Aeronautics and Space Administration (NASA)
• the National Geospatial-Intelligence Agency (NGA) of the U.S. Department of Defense (DOD)
• the German and Italian space agencies.
It was managed by NASA’s Jet Propulsion Laboratory, Pasadena, CA, for NASA’s Science Mission Directorate, Washington, D.C.
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This stereoscopic (anaglyph) view of the pre-quake topography of the area clearly shows the fault that is apparently responsible for the earthquake as a prominent linear landform immediately southwest of the city (image center) and as a series of fault traces that extend westward along the full length of Haiti’s southern peninsula. Notably, a horizontal stream offset along the fault (and adjacent to the city) is very distinct in this view, and displays a left-lateral offset of about 7 kilometers (4.3 miles). Topographic shading plus stereoscopic projection were combined to create this anaglyph view. The shade image was derived by computing topographic slope in the north-south direction. Northern slopes appear bright and southern slopes appear dark. The stereoscopic effect was created by generating two differing perspectives, one for each eye. When viewed through special glasses, the result is a vertically exaggerated view of the Earth’s surface in its full three dimensions. Anaglyph glasses cover the left eye with a red filter and cover the right eye with a blue filter. View Area: One degree latitude (111 kilometers, or 69 miles) by five degrees longitude (525 kilometers, or 325 miles); Location: 18 to 19 degrees North latitude, 70 to 75 degrees West longitude; Orientation: North to the top; SRTM Data Acquired: February 2000 Courtesy of NASA/JPL/NGA |
