They were created as rivers running out of the mountains at the end of the last ice age (about 16,000 years ago) deposited gravel and sand. The Canterbury Plains are flatlands between the Southern Alps and the Pacific Ocean. The fault responsible for the September 4 earthquake had not been mapped because it was buried under the Canterbury Plains. The faults are identifiable by the way they deform the ground. Several faults are scattered across New Zealand’s South Island, and all are associated with the motion of the two tectonic plates.

It happened along an east-west fault that had not been identified before. The September 4 earthquake, however, did not occur on the Alpine Fault. The uplift in the mountains makes it easy for geologists to identify the Alpine Fault. Over time, the motion has built the Southern Alps. The two plates slip past each other in the South Island, creating the Alpine Fault. New Zealand sits on top of the boundary between the Pacific and Australian tectonic plates. Made from data from the Shuttle Radar Topography Mission, the map illustrates how geologic activity shaped the region and why it makes Christchurch vulnerable to earthquake damage. As this map shows, the quake was centered about 45 kilometers (30 miles) west of Christchurch.

on September 4, 2010, when a magnitude 7.0 earthquake shook the region. Residents of Christchurch, New Zealand, and surrounding communities were rattled awake at 4:35 a.m.

Quake map new zealand