Clues left by the Alpine Fault's last big quake reveal its direction - this will help NZ prepare for the inevitable next rupture.

New research has revealed that the Alpine Fault in New Zealand ruptured from south to north in the magnitude 8+ earthquake of 1717. The direction of the fault rupture is a key question for scientists studying the fault, as it has implications for the intensity of shaking and impacts on infrastructure and buildings. The study used a technique based on observations of slickenlines, or scratches on the fault plane, to determine the rupture direction. The findings suggest that both north-to-south and south-to-north ruptures are possible in future earthquakes on the Alpine Fault, with the latter causing higher intensity shaking in populated regions. This information can contribute to better preparedness for the next major earthquake on the fault. [Extracted from the article]