Question

case 2: new zealand
what geological event is most likely to occur at this plate boundary in the future?
the south island of new zealand will split in two, forming a new sea.
a major earthquake — magnitude 7 or 8 — will occur somewhere along the plate boundary.
magma will push up from the mantle, forming a new volcano.
an existing volcano will erupt.
image of new zealand’s islands (south island in gold, north island in green) with inset map; credit: nasa goddard space flight center

Explanation:

New Zealand lies on the boundary of the Australian and Pacific tectonic plates, which are active and prone to seismic activity. Major earthquakes (magnitude 7 or 8) are common at such plate boundaries due to the stress accumulation and release from plate interactions. The other options are less likely: splitting a large island like the South Island suddenly is not typical of plate movement timescales, and forming a new volcano or erupting an existing one is less probable than a major earthquake in this context.

Answer:

A major earthquake — magnitude 7 or 8 — will occur somewhere along the plate boundary.