07-31-2014, 06:31 PM
The boundary at the coast is right at Haena (Shipman Beach). Here's a map; the beige color and everything to the southeast is Kilauea flows, and the blue/green to the northwest of that is Mauna Loa (with a little bit of Mauna Kea flows at the top; the MK/ML line is pretty much right at the Wailuku River):
http://i.imgur.com/09HypTo.jpg
Basically, the ahupuaa of Keaau including the main Puna subdivisions is all one big eruption from Kilauea, which is the northernmost. The only exception is a triangular piece consisting of Keaau town itself and the the farmland to the west and north (mostly mac nuts), which is Mauna Loa (you can sort of see it from the ag roads; North Road and South Road form the boundaries). Given this odd "appendage" on Keaau, and that Olaa is landlocked, I think most of what's now Keaau was originally part of Olaa ahupuaa and was joined to Keaau after it became useless due to the eruption (which was only ~250-400 years ago).
http://i.imgur.com/09HypTo.jpg
Basically, the ahupuaa of Keaau including the main Puna subdivisions is all one big eruption from Kilauea, which is the northernmost. The only exception is a triangular piece consisting of Keaau town itself and the the farmland to the west and north (mostly mac nuts), which is Mauna Loa (you can sort of see it from the ag roads; North Road and South Road form the boundaries). Given this odd "appendage" on Keaau, and that Olaa is landlocked, I think most of what's now Keaau was originally part of Olaa ahupuaa and was joined to Keaau after it became useless due to the eruption (which was only ~250-400 years ago).