Posts: 968
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Joined: Aug 2007
since this topic has gone so far afield...
the biggest (as in size of event, not immediacy of time) type of geologic event that could effect our lives (it's a long shot I know) is the catastrophic failure of a large portion of one of the many volcanoes that make up the islands. hawaiian landslides are awesome to consider, and when I look at the size of these things.. almost too large to believe. I found these links to be interesting..
http://walrus.wr.usgs.gov/posters/underlandslides.html
http://www.mbari.org/volcanism/Hawaii/HR-Landslides.htm
By the looks of this new slow moving flow heading NE. It may take some time to move down the mountain due to the gradual slope and its terrain. What I am seeing though is a wider path, that spreads out farther. Hawaiian acres, Ainaloa, eventually Paradise park look like the eventual path. So is there any way to cut trails from say 1 0r 2 road in Hawaiian acers, Would be a great adventure. Personally I have walked well over 12 miles roundtrip to sit next to the flows down in Kalapana at least 2 dozen times. And looking at the distance through those woods right now looks a whole lot shorter?. The flow does not seem to be in the VNP so how possible could this be now?. If I go for it, should I leave markers along the way, and what kind of markers?. Down Kalapana I used the glow sticks and large built fires to guide directions when there is no moon. Anyway this may not be lunch on the crater, but the flow does cook a good steak by close hangers. And the sounds, sights, and warmth are just some of the amazements.
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dakine and anyone else interested: here's a paper about the ages of the islands, including actual dates (based on radioactive decay dating) and calculated dates (based on subsidence modelling), and estimated maximum height (these are all dates above water; as geochem said, a lot of time is spent getting up from the seafloor). The maximum size above water can be determined by the steep drop off that occurs where lava hits the ocean compared to the flatter flows on land.
https://drive.google.com/file/d/0B9Ytj7j...M4c2Z4U0E/
The maximum anything could have been evolving in the islands is about 30 million years, because between Kure and the previous island there was a gap where no islands were above water, except possibly small atolls. Also, between Kauai and Gardner (which was once about the same size as the Big Island, probably why it's still a bit above water today), the islands were small and didn't last very long before sinking and becoming like Kahoolawe. So to get to Kauai from the previous island with wet forest (Gardner) was a big jump, and not many things made it. There are only a few native plant or animal groups that are older than Kauai, namely the pomace flies (Drosophila), damselflies, and lobelioids (oha wai). The Drosophila are the oldest, at about 22-25 million years.
