The industrial port city of Kobe, Japan, was hit by history's costliest earthquake ($100 billion in property damage) at 5:46 a.m. on January 17, 1995. The 30-mile (50-km) long fault rupture passed directly through the world's third-busiest port and home to 1.5 million people. With little warning 6,308 died in Kobe before sunrise on that cold January morning. The rupturing event lasted 15 seconds, moved each side of the fault more than six feet (1.7 m) horizontally relative to the other side, and uplifted the land by three feet (1 m). The many areas of unconsolidated sediment in and around Kobe saw some of the worst damage, and shook for as long as 100 seconds because of the natural amplification of the seismic waves. Liquefaction was widespread and caused much of the damage, including collapse of buildings and port structures and destruction of large parts of the transportation network. Water, sewer, gas, and electrical systems were rendered useless. More than 150,000 buildings were destroyed in the initial quake, and a huge fire that started from ruptured gas lines consumed the equivalent of 70 square blocks.
These examples of convergent margin earthquakes show that the strongest, deadliest earthquakes tend to occur at convergent margins. Areas thousands of miles (km) long can suddenly slip in one large earthquake event, generating fast-moving seismic waves, giant tsunamis, landslides, shifts of land level, and indirect effects such as fires, disease, and loss of livelihood for millions. Convergent margin earthquakes are capable of releasing more energy than any other catastrophic Earth event, and are therefore among the most destructive forces of nature. When considered with the volcanic eruptions that characterize many sections of convergent margins it is clear that these beautiful, mountainous areas are among the most hazardous on Earth.
See also accretionary wedge; continental crust; deformation of rocks; granite, granite batholith; island arcs, historical eruptions; metamorphism and metamorphic rocks; plate tectonics; structural geology; volcano.
Moores, Eldridge, and Robert Twiss. Tectonics. New York:
W.H. Freeman, 1995. U.S. Geological Survey. "Earthquake Hazards Program."
Available online. URL: http://earthquake.usgs.gov/.
Accessed October 31, 2008.
Copernicus, Nicolaus (1473-1543) Prussian (Polish or German, disputed) Astronomer, Mathematician, Physician, Economist, Military Leader,
Diplomat Nicolaus Copernicus is credited with being one of the earliest scientists to propose a scientifically sound model with the Sun as the center of the universe, displacing the Earth from this role in earlier models. His heliocentric model was described in his book De revolutionibus orbium coelestium (On the Revolutions of the Celestial Spheres, 1939), which many regard as the starting point of modern astronomy and the beginning of a revolution in science known as the Copernican revolution.
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