Looking at Tectonics

The devastating earthquake that tore through Christchurch on the afternoon of February 22 is the product of a new fault line in the Earth’s crust — an offshoot from the Alpine fault — that seismologists were previously unaware of. “It’s not a new fault in the sense that it has only just been created but it is a new fault that has only just been discovered,” Dr Roger Musson, head of seismic hazards and archives at the British Geological Society, told The Independent. “Some fault lines are very easy to see but the one under Christchurch is covered by sediment and would have been invisible without thorough geophysical searches.” New Zealanders have long known that their mountainous country is acutely vulnerable to tectonic movements. Major fault lines dissect the nation, snaking up the western coast of the South Island before splitting in two just south of Wellington. “Wellington has always been considered much more at risk [than Christchurch] because it straddles the plate boundary,” Australian Seismological Centre director Kevin McCue explained. New Zealand experiences around 14, tremors each year, although most are too small to be felt. They are a sign of the tectonic processes that are gradually shredding the country.