Magnitude 4.7 TONGA
Wednesday, April 22, 2009 at 15:18:19 UTC
Earthquake Density Maps
Earthquake Density
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Average number of Earthquakes per Year per 12,300 km2, Magnitude 5 and Greater
Intermediate Earthquakes: Depth 70-300 km
Major Tectonic Boundaries: Subduction Zones -purple, Ridges -red and Transform Faults -green -
Average number of Earthquakes per Year per 12,300 km2, Magnitude 5 and Greater
All Depths
Major Tectonic Boundaries: Subduction Zones -purple, Ridges -red and Transform Faults -green
Global Earthquake Density Maps
Preliminary Earthquake Report
U.S. Geological Survey, National Earthquake Information Center
World Data Center for Seismology, Denver