Alpine Fault Wall Stayed Motionless

In 1964, New Zealand geophysicist Frank Evison commissioned a concrete wall across the Alpine Fault in the South Island's Maruia valley. Surveying markers in the wall let scientists test whether the fault crept gradually or held still between major earthquakes. The wall has stayed straight without moving a millimeter for about 60 years, supporting the view that the fault shifts several meters at once during earthquakes separated by centuries.

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