Thursday, December 4, 2008

A Big Island Geology Tour

Callan suggested that I post the advice I gave him for his recent trip to Hawaii, and since I haven't had time to write anything really meaningful lately (darn you, end-of-semester crunch time!) I think I'll do just that. You can follow along with his fantastic photos and discussion of the locations he visited - I'll link to each of his blog entries as they go up. (Those links are bold.)

These notes are the result of two trips to the Big Island, one that I made for an undergraduate field course, and one for a vacation and to take the Center for the Study of Active Volcanoes (CSAV) Field Methods in Volcanology class. (I highly reccommend that - where better to train to be a volcanologist than on an active volcano?) In addition, I've put all of these locations and some notes on a Google Map, and some of my own photos here. Enjoy!

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Kona area:
  • About two miles south of Kona on Alii drive is the best snorkeling beach I've been to. It's a public park whose name escapes me, but it's a right turn off Alii before you get to Royal Poinciana Drive. They have snorkel gear rentals, so you don't have to bring your own, and it's an awesome place to see all sorts of fish and sea turtles, which come right up to the beach.
  • Two miles north of the Kona Airport on Rt. 19 is the 1801 Kaupulehu lava flow on the Hualalai volcano. If you're coming from the airport, a large lava tube entrance will be visible on the right side of the road. This is a fantastic exposure of mantle xenoliths - really big chunks of dunite and (I think) websterite - and you can hike a short distance into the lava tube.

Southern Big Island:
  • In addition to the green sand (Mahana or Papalakoa) beach, you should definitely try to get to South Point (Ka Lae), the southernmost point in the US. The cliffs make for a great view, and there's a sea cave to look into. (Some people jump into this thing, which I think is nuts.)

  • The Punaluu Black Sand Beach is another great place for sea turtles, although the waves are too rough for much snorkeling; there is also a resident population of scruffy stray kittens. I also highly recommend stopping at the Punaluu Bake Shop in Na'alehu for some malasadas (Portuguese doughnuts) and lunch.

Hawaii Volcanoes National Park:
  • I don't know if they're letting people near Halemaumau Crater anymore, but if you can get down there, on the other side of Crater Rim Drive from the overlook is the Halemaumau trail, which is a great place to see ballistic blocks from the 1920s eruptions, as well as an old airfield that got plowed up when the Japanese attacked in WWII.
  • The Kilauea Iki hike is a great way to see the crater from the bottom, and you can look into the vent of a fire fountain that erupted in the 60s.

  • If you can hike the caldera, there are great spatter ramparts along the Halemaumau trail.
  • Devastation Trail, which runs behind Pu'u Pu'ai (the cone that formed from the Kilauea Iki eruptions) is a good place to look for Pele's tears, and get a good look at local flora and fauna (we saw lots of birds along here, and the ohia trees and ohelo bushes are pretty common). You can eat ohelo berries along the way, if you want - they get dark red when they're ripe, and make delicious jam. (Be sure to leave an offering for Pele to say thanks, though - she's kind of a touchy goddess.)

  • Thurston Lava Tube is definitely worth a visit, and if you bring a headlamp (a good one, and maybe an extra flashlight), you can hike all the way to the back of the unlit section, where most of the tourists don't go.
  • Along Chain of Craters Road, before you get to the active flow fields, there's an overlook and parking area next to a collapsed lava tube. If you follow the tube over the flow fields to the north, it leads all the way back to the summit of Mauna Ulu. (It's a long hike and you either have to go back the same way or have someone meet you along one of the other roads afterwards, though, and sometimes the access roads are closed.)
  • Coconut Island in Hilo Bay has records of tsunami inundation heights posted on trees; it's also a good lunch and swimming spot.
  • The Boiling Pots are a neat series of waterfalls and plunge pools that the locals go to for swimming (and for launching themselves off of cliffs). There's a public parking area and picnic tables, but this is a good place to keep a close eye on your stuff. (Be careful to stay out of people's backyards, too, because some of them grow marijuana and they're a bit touchy about trespassers...)

Mauna Kea:
  • Definitely drive up to the summit. It's probably best to do this from the Hilo side, since there are no gas stations in the center of the island and you'll need a full tank to get up and down. There's an unpaved stretch of road between the ranger station at 9000 feet and the summit (13,000 feet) which is pretty grueling, but it's worth the drive if you take your time. When you get to the observatories at the summit, be sure to hop over the railing and climb the small cinder cone with the shrine on top - that's the real summit, and where you'll find the Mauna Kea benchmark. Be sure to spend at least an hour at the ranger station, though, and chug a few nalgenes of water before you try to go to the top - you'll be less likely to get altitude sickness. It's also a great place to see silversword plants, which are very rare.

  • The ranger station has astronomy sessions in the evenings where students from UH Hilo help set up telescopes for moon and planet viewing. It gets extremely cold, but they sell coffee and tea and ramen that you can heat up in their microwave.
  • Below the summit of Mauna Kea, around mile 6 of the access road, there's a small pulloff (on the right as you're driving up). If you hike out a bit over the scoria, there are some flat-topped rocks. Have a look at the top of these - this is the closest point one of the closest points to the equator that you can find evidence of glaciation! There are glacial striations here, and the debris surrounding the outcrop is supposed to be remnants of a glacial moraine. (There are a lot of glacial features up there, but I didn't get to see them all - the rangers will probably be able to steer you to them.)

Kohala Coast:
  • Laupahoehoe Beach Park has a monument to the people who were killed in the 1946 tsunami. It's a beatiful place to camp, and they've installed tsunami warning sirens since the 40s.
  • Waipio valley is absolutely worth the climb down the ridiculously steep road to get to the beach - some people will drive down, but I'd recommend not risking a rental car on it. Great saprolite exposures at the top of the road. If you make it to the far end of the beach (it takes a little stream-fording), you can see cliffs that expose a number of the lava flows that make up the ancient Kohala volcano. There are also boulders of some really funky lavas here; we found one piece that was chock full of huge plagioclase phenocrysts. Watch out for the donkeys that live in the area - they bite - and pay attention to the "kapu" signs; this used to be a burial ground for Hawaiian kings. I wouldn't recommend much swimming - the surf is very rough and the area is known for sharks.

  • Off Rt. 137 (Kapoho-Kalapana Rd), which you have to approach from the east or north (since the current flow field took out the ocean road), there is a black sand beach and breadfruit/palm tree molds. This is the remains of the Kalapana Gardens subdivision; the people who still live there planted hundreds of coconut palms along the newly formed beach here.
  • On Rt. 250 (Kohala Mountain/Hawi Road) north of Waimea (the north end of the island), there's a lava dome of benmoreite associated with late-stage, secondary melts from the Kohala volcano. I'm not sure of the exact location, but it's a light-colored roadcut with a bit of an overlook down on the Waimea valley. The benmoreite is probably one of the most felsic rocks on the island, so it's a bit of a novelty. (There are other benmoreites on Mauna Kea, but this is the only one I've seen.) *Sadly, I don't have a photo of the outcrop, but this website does.
For those of you who want more detailed geological descriptions than I've been providing, the USGS has some good Open-File geologic maps of the islands, and Hawaii Volcanoes National Park sells more detailed ones (as well as topo maps with trails marked).

A few safety reminders:
If you're going out hiking on the lava fields (or anywhere else in Hawaii, for that matter), make sure you have the right gear, enough water and lots of sunscreen. Hawaii is much closer to the equator than most people realize, and it is very easy to get dehydrated and sunburned there (a really bad combination). I saw far too many people on both of my visits without proper hiking gear (sturdy shoes, long pants, hats, sunglasses, etc). Thick work gloves are also important for hiking on lava - when you fall, you tend to break your fall with your hands, and believe me, you don't want to grind volcanic glass into them. Also, if you'll be anywhere near hot lava, don't wear thin synthetic clothing. Picking melted nylon off your skin is not a fun exercise, no matter how great your new bug-zapper button-down is. Natural fabrics (cotton and linen) will scorch but not melt.

For a short hike (no more than a mile or two), bring at least two Nalgenes of water. For a long hike, bring a least a gallon - that's at least four Nalgenes. It's heavy, but you'll drink all of it, because it gets darned hot out there. Follow the same rules you would if you were in a desert - there is nowhere on those lava fields to get water, and rainwater that collects in hollows is often filled with nasty microscopic critters. Don't ever go hiking off-trail without an experienced guide, and certainly don't do it in flip flops. (I have seen people do this, and it is truly shocking.)

That said, Hawaii is a truly awesome place to explore, and even better if you do it safely. Watch out for yourselves!


Chuck said...

"this is the closest point to the equator that you can find evidence of glaciation!"

Um, the Andes? Kilimanjaro?

Tuff Cookie said...

Thanks for the catch. I'll fix that.