These QuickTime movies show the East Pacific Rise. The first is a flyover of the topography around 9°N. The second shows video of ALVIN and of the seafloor along the spreading axis in the same area. The third is footage from 17-18°S, and the last is just for fun.


EPR flyover

The first few seconds show a still of the East Pacific Rise near 9-10°N looking to the North. (The area is ~100X100km) The hot colors (red, yellow) are shallow depths, less than 2800m; greens and blues are deeper extending to a maximum depth of ~3300m. (Vertical exaggeration is ~40X.) The spreading center here is an axial high (in yellow and red) which rises ~200-400m above the older seafloor.
Most of the volcanic and hydrothermal activity occurs along an axial summit trough along the center of the axial high, the trough is only ~10m deep and ~50m wide so it is too small to be seen in this map. The rough topography in blue and green which parallels the axial high is formed by volcanic growth faults and the structures are called the abyssal hills (see Macdonald, K. C., P. J. Fox, et al. (1996). Volcanic growth faults and the origin of Pacific abyssal hills. (Nature 380: 125-129., full text and figures available on this web page). The flyover begins at the north end of the map flying over the axial high and then over abyssal hills. The hills become particularly large and separated by large basins as we go south because this is the off-axis discordant zone of an overlapping spreading center which occurs at 9°N just south of this mapped area (see Macdonald, K. C. and P. J. Fox (1990). The mid-ocean ridge. (Sci. Am. 262: 72-79. Full text and figures available on this web page). The final pass heads north right along the spreading axis, hang onto your seats! The large version has several more flyovers at better resolution.
The original of this animation was produced by Larry Mayer, now at Univ New Hampshire using data from Wilcock, W. S. D., D. R. Toomey, et al. (1993). The renavigation of Sea Beam bathymetric data between 9°N and 10°N on the East Pacific Rise. Mar. Geophys. Res. 15: 1-12.


These are a few clips from dives using the submersible ALVIN (funded by NSF, operated by WHOI). MANY scientists participated in this effort, for an introduction to the ARGO and ALVIN expeditions, see Haymon, R. M.; Fornari, D. J.; Edwards, M. H.; Carbotte, S.; Wright, D.; Macdonald, K. C., 1991,
Hydrothermal vent distribution along the East Pacific Rise Crest (9 09-54N) and its relationship to magmatic and tectonic processes on fast-spreading mid-ocean ridges, Earth Planet. Sci. Lett., 513-534, Haymon, R. M., and 14 others, 1993, Volcanic eruption of the mid-ocean ridge along the East Pacific Rise crest at 9 45-52N: Direct submersible observations of seafloor phenomena associated with an eruption event in April, 1991: Earth Planet. Sci. Lett., v. 119, p. 85-101.
Scene 1: Ken Macdonald climbing on board ALVIN for a dive on the site of the 1991 eruption. The sub holds 3 people.
Scene 2: Surface divers check out ALVIN making sure it is ready to submerge. ALVIN will sink like a stone, taking 1 1/2 hours to reach the bottom. It becomes pitch black about 500m deep and this dive will go to 2600m.
Scene 3: On the seafloor at a depth of ~2600m on the crest of the East Pacific Rise between 9 45N to 9 52N. The glassy black lava flow of April 1991 lies on top of older, grey lavas, probably decades old. The field of view in the video clips is typically 1-5 m across.
Scene 4: The ALVIN robotic manipulator is used to collect a sample of the very glassy delicate 1991 lava flow. The orange columns in the background are hydrothermal chimneys made of polymetalic sulfides.
Scene 5: The 1991 lava flow killed a large number of tubeworms as the 1200° C lava barbequed the hapless victims. All that are the white tubes of the worms enveloped by the flow. The area is called Tubeworm BBQ.
Scene 6: One of the biggest surprises was that the 1991 eruption was accompanied by a blizzard of white bacterial material. Some the bacteria may have been released from depth within the crust during the eruption; in addition the eruption may have introduced enough nutrients into the system to produce a bacterial bloom.
Scene 7: Another shot of the recent lava flow completely covered by bacterial material, here it appears that some of the bacterial matter is being ejected out of a hole in the lava crust.
Scene 8: With all of the carnage on the seafloor after the eruption, it does not take long for predators to move in. These are brachyuran crabs which consume the white bacterial snow and, in this scene, are attacking one of the surviving tube worms.
Scene 9: A trio of black smoker hydrothermal vents. The water exits at ~350-400C. The water is blackened by polymetalic sulfide particles which precipitate upon contact with seawater. The chimneys are very small because they are only a few weeks old.



Based on an ARGOII survey of the super-fast spreading East Pacific Rise at 17-18°S (EPR ARGO). I added some music and sound effects to this for amusement. Rachel Haymon was the Chief Scientist, Ken Macdonald was the Co-Chief Scientist; other scientists included Scott White, Dan Scheirer, Dawn Wright, Lisa Crowder, Susan Baron, Phil Sharfstein, Laura Magde, Cindy Van Dover, and I know I am forgetting someone.



Windsurfing at the Gorge: One of my favorite activities is windsurfing during the summer at the Columbia River Gorge. The first shot is actually at Lake Isabella for an early season session in brrrr 50 degree water; the second shot is at Bobs Beach in the Gorge in 1999 with steady 20-30 mph winds. I am on a Northwave 5.2. My buddy George has the black and white sail and is trying to beat me upwind, but for once he loses!