The Hellenic Navy (HN) (Greek: Πολεμικό Ναυτικό, Polemikó Naftikó, abbreviated ΠΝ) is the naval force of Greece, part of the Greek Armed Forces. The modern Greek navy has its roots in the naval forces of various Aegean Islands, which fought in the Greek War of Independence. During the periods of monarchy (1833–1924 and 1936–1973) it was known as the Royal Navy (Βασιλικόν Ναυτικόν, Vasilikón Naftikón, abbreviated ΒΝ).The total displacement of all the navy's vessels is approximately 150,000 tons.The motto of the Hellenic Navy is "Μέγα το της Θαλάσσης Κράτος" from Thucydides' account of Pericles' oration on the eve of the Peloponnesian War. This has been roughly translated as "Great is the country that controls the sea". The Hellenic Navy's emblem consists of an anchor in front of a crossed Christian cross and trident, with the cross symbolizing Greek Orthodoxy, and the trident symbolizing Poseidon, the god of the sea in Greek mythology. Pericles' words are written across the top of the emblem. "The navy, as it represents a necessary weapon for Greece, should only be created for war and aim to victory."...............The Hellenic Merchant Marine refers to the Merchant Marine of Greece, engaged in commerce and transportation of goods and services universally. It consists of the merchant vessels owned by Greek civilians, flying either the Greek flag or a flag of convenience. Greece is a maritime nation by tradition, as shipping is arguably the oldest form of occupation of the Greeks and a key element of Greek economic activity since the ancient times. Nowadays, Greece has the largest merchant fleet in the world, which is the second largest contributor to the national economy after tourism and forms the backbone of world shipping. The Greek fleet flies a variety of flags, however some Greek shipowners gradually return to Greece following the changes to the legislative framework governing their operations and the improvement of infrastructure.Blogger Tips and Tricks
This is a bilingual blog in English and / or Greek and you can translate any post to any language by pressing on the appropriate flag....Note that there is provided below a scrolling text with the 30 recent posts...Αυτό είναι ένα δίγλωσσο blog στα Αγγλικά η/και στα Ελληνικά και μπορείτε να μεταφράσετε οποιοδήποτε ποστ σε οποιαδήποτε γλώσσα κάνοντας κλικ στη σχετική σημαία. Σημειωτέον ότι παρακάτω παρέχεται και ένα κινούμενο κείμενο με τα 30 πρόσφατα ποστς....This is a bilingual blog in English and / or Greek and you can translate any post to any language by pressing on the appropriate flag....Note that there is provided below a scrolling text with the 30 recent posts...Αυτό είναι ένα δίγλωσσο blog στα Αγγλικά η/και στα Ελληνικά και μπορείτε να μεταφράσετε οποιοδήποτε ποστ σε οποιαδήποτε γλώσσα κάνοντας κλικ στη σχετική σημαία. Σημειωτέον ότι παρακάτω παρέχεται και ένα κινούμενο κείμενο με τα 30 πρόσφατα ποστς.........

Wednesday, October 20, 2010

Glaciers flow downhill,..[ 1904 ]

Susitna Glacier, Alaska
Susitna Glacier, Alaska

Google Earth file (25 KB, KML) acquired August 27, 2009
 
 
Earth Observatory
Posted October 20, 2010
  
Like rivers of liquid water, glaciers flow downhill, tributaries joining to form larger rivers. But where water would rush, ice crawls. As a result, glaciers gather dust and dirt, and bear long-lasting evidence of past movements. That was the case on Alaska’s Susitna Glacier on August 27, 2009, when the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA’s Terra satellite passed overhead.
This false-color image looks similar to an areal photograph, except that vegetation is red. Susitna Glacier’s surface is marbled, combining dirt-free pale blue and dirt-coated dark brown ice. Infusions of relatively clean ice push into the glacier from tributaries flowing from the north. The glacier surface appears especially complex near the center of the image, where ice from a tributary has pushed ice in the main glacier slightly southward.
A photograph taken by the U.S. Geological Survey and archived by the National Snow and Ice Data Center shows an equally complicated surface of Susitna Glacier in 1970, with dirt-free and dirt-encrusted surfaces forming stripes, curves, and U-turns.
Susitna Glacier flows over a seismically active area. In fact, a 7.9-magnitude quake struck the region in November 2002, along the previously unknown Susitna Glacier fault. Although geologists surmised that this and other earthquakes left steep cliffs and slopes on the glacier surface, the complex glacial surface apparent in this image results from surges of tributary glaciers.
Glacier surges—typically short-lived events where a glacier moves many times its normal rate—can occur when meltwater accumulates at the base of the glacier. The water provides lubrication that quickens flow. This water may be supplied by meltwater lakes that accumulate on top of the glacier, and melt ponds appear on the Susitna Glacier, in the lower left corner of this image. The nature of the underlying bedrock might also contribute to glacier surges, with soft, easily deformed rock leading to more frequent surges.

  1. References

  2. Crone, A.J., et al. (2004). The Susitna Glacier thrust fault: Characteristics of surface ruptures on the fault that initiated the 2002 Denali Fault earthquake. Bulletin of the Seismological Society of America, 94(6B), S5–S22.
  3. Eberhart-Phillips, D., et al. (2003). The 2002 Denali Fault earthquake, Alaska: A large magnitude, slip-partitioned event. Science, 300(5622), 1113–1118.
  4. Photojournal. (2010, September 7). Susitna Glacier, Alaska. NASA Jet Propulsion Laboratory. Accessed October 19, 2010.
  5. U.S. Geological Survey. (1990). Largest rivers in the United States. (PDF file). Accessed October 19, 2010.
NASA Earth Observatory image created by Jesse Allen and Robert Simmon, using data provided courtesy of NASA/GSFC/METI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team. Caption by Michon Scott.
Instrument: Terra - ASTER
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