Did primary or secondary seismic waves cause the 2011 New Zealand Earthquake?

There are 3 basic types of earthquake waves generated by an earthquake. P waves (Primary - compressional waves) and S waves (Secondary- shear waves) are often called body waves. They travel through the "body" of the Earth and are not destructive. The third type of earthquake wave is called the L wave. These are the surface waves and are responsible for the shaking experienced at the Earth's surface and the resulting damage.

Most earthquake damage is not done by so-called primary (P) or secondary (S) waves, but by surface waves (L and R). In a sense, surface waves *are* secondary waves in that they are not produced at the earthquake focus but by P and S waves interacting with the earth's surface. S waves do generally have a slightly larger amplitude than P waves. In addition, while P waves simply compress and expand the ground along the direction of wave motion, S waves move the ground from side to side, which causes more stress (torque) at the surface and on any objects built there, so they would be more damaging than P waves.

Neither,
The cause was the Pacific Plate subducting beneath the Australian Plate
The earthquake produced both types of waves

As in all earthquakes the secondary (S) wave caused most of the damage. The primary (P) wave arrives early and has the movement analogous to a horizontal slinky. The S wave arrives later (time is dependent on distance) and its movement is like swinging a rope tied to a post. The difference in arrival times is proportional to the distance to the fault break.