Stop 9: H-3 Quarry
Much of the northern ("windward") side of Oahu experience giant landslides many tens to hundreds of thousands of years ago. These landslides exposed part of the Koolau volcano that were once more than 1 km beneath the surface. This provides geologists with an excellent opportunity to study the insides of the volcano.
Here we see George Walker standing next to a 1 m-wide dike along the axis of the old Koolau volcano rift zone. Hundreds of dikes of this size were intruded into the volcano, forcing the eastern side of the mountain towards the east. Eventually, this resulted in the over-steepening of the land mass, and its subsequent collapse onto the ocean floor during a giant landslide that spread more than 200 km from the shore.
From here you can continue on to Stop 10 on the ground.
Return to Southeast Oahu Virtual Field Trip
Author: Peter Mouginis-Mark
Copyright by P. Mouginis-Mark
Curator: Lori Glaze