Earth Observations taken by the Expedition 13 crewmember

ISS013-E-67242 (15 Aug. 2006) --- Christchurch, New Zealand is featured in this image photographed by an Expedition 13 crewmember on the International Space Station. Snow highlights the peaks of the Banks Peninsula to the southeast of the city. The Peninsula has a radically different landscape compared to the adjoining flat Canterbury Plains on which Christchurch is situated. This is a result of the geology of the Banks Peninsula -- it is formed from the overlapping cones of the extinct Lyttelton and Akaroa volcanoes. Subsequent erosion of the cones formed the heavily dissected terrain visible in the image, and sea level rise led to the creation of several harbors around the Peninsula. Erosion continues unabated today, as evidenced by the apron of greenish blue sediment-laden waters surrounding the Banks Peninsula. Other features of interest in the image include the braided Waimakariri River to the north-northwest of the city, and the greenish brown waters of Lake Ellesmere. The coloration of the water is due both to its shallow depth (1.4 meters average) and its high concentrations of nitrogen and phosphorus - conditions which lead to a high abundance of green algae.