Sand Liquefaction

April 10, 2003

Pict0017 copy

Provided by: Al Chang, NASA/GSFC
Summary authors & editors: Al Chang; Jim Foster

The above photograph of a road-cut was taken last month and shows the signature of the 1995 Great Hanshin and Awaji Earthquake (also known as the Kobe-Osaka Earthquake). This quake was a magnitude 7.2 on the Richter Scale, and it occurred along the Nojima Fault on January 17, 1995 -- it originated about 1.4 km below the surface. Approximately 6,400 people were killed in this quake, and the city of Kobe was devastated. The sand layer shown in the road-cut was shaken so severely that it behaved more like a fluid than a solid during the quake. When soil shakes with sufficient force, sand will liquefy. Most structures built atop sand layers in Kobe collapsed. Vertical displacement along the fault was typically 20-40 cm, but in some areas, the vertical lift and the lateral displacement was over 1 m.

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