The Kaikoura Earthquake was the “Most Complex Earthquake Ever”

Fagjun | Published 2017-03-25 07:22

New findings are coming to light about last year's Kaikoura earthquake.

In November of last year, a 7.8-magnitude earthquake tore through the South Island of New Zealand. In a span of about two minutes, ruptures appeared along an almost 200 kilometer-long tract of land. The earthquake also lifted large blocks of land upwards by up to eight meters.

Giant cracks ran along the ground, highways broke up into pieces, railway lines rose off the ground, and beaches rose away from the sea. The town of Kaikoura also rose by 70 centimeters. The earthquake caused these things and more, but it also caused something else more shocking.

This is a satellite image of the town of Kaikoura before the earthquake.
[Photo by NASA]

Here is another satellite image of Kaikoura, taken after the earthquake. Notice that there is now more exposed land, which indicates that the land rose up higher during the quake.
[Photo by NASA]

Mapping the Kaikoura Earthquake

A new study now reveals that the earthquake also shifted parts of the South Island closer to the North Island by as much as five meters.

According to the researchers, this study can help scientists rethink their understanding of how earthquakes work. The Kaikoura earthquake may be the most complex earthquake ever studied, the study claims. The researchers say that current models on earthquakes could not have predicted its characteristics.

At least 21 faults ruptured during the quake, which is a record-breaking number. Some of these faults were previously unknown and had only been discovered upon investigation of the massive earthquake.

Surprisingly, there were only two casualties in the quake and a few dozens injured. However, these figures could have been much worse. The complexity of the earthquake was such that even accurately determining the magnitude was difficult. This means that scientists need to reconsider early warning systems in use today. Standard hazard models will not be able to handle an earthquake with this kind of complexity.

Hazard models are important making sure that people will be able to cope with an earthquake well. These models predict the type of ground shaking, recurrence period, and maximum magnitude. Thus, they serve as a guide to building codes that keep residents of an area safe in the event of an earthquake.

The complexity of the Kaikoura earthquake is already challenging these hazard models as well as other long-standing ideas about earthquakes. Thus, current models and understandings may be too narrow for future earthquakes that may prove to be too complex.

Researchers continue to study the earthquake, which fortunately had a lot of documentation. Hopefully, sooner rather than later, they can come up with new models on how to understand earthquakes that may be as complex as the Kaikoura earthquake.

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