In New Zealand, people lie at the interface of the Indo-Australian and Pacific tectonic plates. According to history, these two plates have been grinding against each other for millions of years. Nonetheless, the outcomes for these collisions have three distinct outcomes which vary according to the specific location within New Zealand. In between these two tectonic zones, lies the Alpine fault which extends to the south of New Zealand from Greymouth and disappears into the ocean approximately 12 km from Milford. The alpine fault reportedly has fractured four times since its formation at intervals of about 150-350 years (Van Avendonk et al, 2013,p.251); with the last fracture believed to have been back in the year 1717.
Therefore, it becomes apparent that, the recent Christchurch earthquake of February 2011 is largely associated to a fracture of the Alpine fault. However, the earthquake was not considered to being a direct fracture of the Alpine fault but as a result of the great pressure that is exerted between the two plates whereby, the Alpine Fault shows the greatest explicit signs. Therefore, instead of fracturing at the boundary, this particular earthquake was considered to have involved fractures within the various fragments of the Pacific plate especially where Canterbury lies. Around this locality, there has been recorded history of earthquakes of magnitude 8 and beyond (Van Avendonk et al, 2013,p.250). In fact most people consider Wellington and Canterbury to being the most prone regions in regard to earthquake risk in the whole of New Zealand as a result of movement of tectonic forces.
Conclusively, it is evident that the tectonic tension that was caused and resulted to the current earthquakes that have been hitting the region around the Alpine fault. Nonetheless, the new understanding as a result of these earthquakes caused by the tectonic forces between the two great plates can be used to explain future tectonic activities that may occur in this region of New Zealand.
References
Van Avendonk, H. J., Holbrook, W. S., Okaya, D., Austin, J. K., Davey, F., & Stern, T. (2013).
Continental crust under compression: A seismic refraction study of South Island Geophysical Transect I, South Island, New Zealand. Journal of Geophysical Research: Solid Earth (1978–2012), 109(B6).
