The New Zealand earthquake, which struck the country's second-largest metro area shortly before 1 p.m. local time Tuesday, highlights the hazards of living along the Pacific's "ring of fire."

Around its perimeter, vast plates of Earth's crust grind past or under one another, triggering some of the planet's most powerful earthquakes and most explosive volcanoes.

The magnitude 6.3 temblor that hit Christchurch Tuesday comes a scant five months after a magnitude 7.0 quake struck the region – the same magnitude as the earthquake that flattened much of Port-au-Prince, Haiti on Jan. 12, 2010. (Initial reports indicated September's earthquake had a magnitude of 7.4, but later estimates revised this downwards to 7.1 and then 7.0.)  [ CSMONITOR.com ]