Today's photographic tour comes courtesy of my nephew Jacob, who worked hard the last few years to save enough for a tour of the Hawaiian Islands. One of his adventures was a boat tour off the coast of the Big Island where the Pu'u O'o flow has been pouring into the Pacific for much of the last quarter century. A boat tour this close to the fresh lava flows is something I haven't had the opportunity to do yet.The lava is erupting from the East Rift Zone of Kilauea, and flows for six or seven miles through a system of lava tubes until it reaches the coast. One of the lava tubes (in the picture above) has been breached by wave erosion.
The lava flows are still extremely hot, even after traveling for miles (the lava tubes are an excellent insulating environment). As they emerge from the tubes, they flow like thick syrup, forming so-called pahoehoe lavas.
Here, another lava flow spilled over the edge of a seacliff. It didn't take the waves long to cut into the base of the flow. Looking at the cliff exposure, it is easy to see why very few streams can be found on this part of the Big Island. Any rain immediately seeps into the subsurface through the system of cooling fractures.
At times, the lava flows directly into the water and shatters on contact, forming black sand beaches (above). Hawaii is unique in the variety of sandy beaches; some are composed of coral fragments and are white, some are reddish, from weathered iron-rich basalt, some are black, and a precious few beaches are composed of bits of olivine, and are green.
Wave action can quickly enlarge openings, forming sea caves. Arches are also produced by the waves, but they don't tend to last for very long. Jake, you have the makings of a real geologist! Thanks for sharing these great photographs!
