Hunua Falls

Hunua Falls are on the Wairoa River that follows the route of the Wairoa Fault. This fault has uplifted basement greywacke rocks on the east side and downthrown them on the west into a shallow half graben that has accumulated pumice-rich sediment above the falls.
About 1.3 million years ago magma rose up along the fault and erupted a small basalt volcano here at the surface. Erosion since then has removed most of the volcano except some of the tuff ring and filled crater. The gently sloping sides of the eroded crater can be seen in the cliffs on either side of the falls. Outside the crater the cliff is made of bedded tuff (volcanic ash) that slopes outwards away from the crater. These wet ash beds were erupted during the early wet explosive phase of eruptions of Hunua Falls Volcano. The contents of the crater are displayed in most of the cliff beneath and on either side of the falls themselves. The crater fill was erupted by dry explosive fountaining eruptions and the quiet evulsion of molten lava. The lower parts of teh crater are mainly filled with unbedded agglomerate (volcanic breccia) on the east side and interbedded agglomerate and several harder basalt flows. Higher in the crater fill there is more solidified basalt lava some of which may have cooled in an intrusive vent but there is also an extensive sheet of basalt that was p[robably a molten lava lake within the crater before it cooled and solidified.
Within the tuff forming the eastern edge of the crater there are a number of volcanic bombs and blocks that were explosively ejected from the volcanic vent. Some are angular blocks that were already solid blocks when thrown out, whereas others were still quite hot and plastic when ejected and developed their shape as they flew through the air to become spindle shaped, or were even hotter and less solid and developed a cow-pat bomb shape when they landed.
The Wairoa Fault has low scarps in some places where it crosses the bottoms of side valleys, which indicates it is probably less than 100,000 years since it last ruptured in an earthquake.

Can you see the sloping sides of the crater cut through the underlying tuff ring in the cliffs on either side of the falls?
Can you distinguish the hard basalt from the softer agglomerate in the cliff face east of the falls?
Can you find the large fusiform volcanic bomb beside the track to the bottom of the cliff face east of the falls?
How high are the falls?
The deep pool at the bottom of the falls is not part of the crater - so how was it created?
How much uplift has there been across the Wairoa Fault?
What are the Hunua Ranges largely made of?