Today in Earthquake History

Today's Earthquake Fact:
A seismic wave shadow zone was discovered in about 1910, by measuring how P and S waves travel through the earth and out the other side. From the lack of S waves and a great slowing of the P wave velocity (by about 40%), it was deduced that the outer core is made of liquid. The shadow zone also defined the diameter of the core.

Year at a Glance

July

Note: All earthquake dates are UTC, not local time.

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Year	Location	Magnitude	Comment

1975	Solomon Islands	7.9 7.7	These earthquakes struck the west coast of the island of Bouganville. The magnitude 7.9 earthquake generated a local tsunami that reportedly demolished every house in the village of Torakina. Bouganville Copper Ltd. ordered the evacuation of its giant mine at Panguna. The earthquakes cracked many buildings and caused a number of landslides. A number of magnitude 6 or greater aftershocks were recorded during the first 12-hour period following the main shock. Although many aftershocks were recorded, none caused additional damage. Despite the severity of the earthquakes, no fatalities were reported. From Significant Earthquakes of the World 1975, and Earthquake Information Bulletin, Volume 7, Number 5.

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