A little late-night YouTubeing resulted in these two incredible video finds. Both are from the big island of Hawaii, the first was shot in 1933 during an eruptive event at the Mokuaweoweo Crater at the summit of Mauna Loa. The fissure inside the crater was about 2,000 feet long, with lave fountains streaming hundreds of feet into the air.
The next video was shot in the early part of this year during the eruptions at Pu`u `O`o and Napau Craters. It features a stunning ground-level view of the propagating fissure.
I share these videos with you not just because they are cool in their own right, but also because they’re beautiful footage of fissure eruptions which played a large role in the ancient formation of the Oregon and Washington landscapes. They just played a much larger role. Much.
This map of the northwest states illustrates what is called a Large Igneous Provence. The areas in brown were all inundated by basaltic lava that erupted from fissures or dike swarms in different phases from about 17 to 14 million years ago.
The lava flows are collectively known as the Columbia River Basalt Group and they dominate the landscape in much of the northwest.
So, as you watch the videos above, imagine the size and number of fissures that would be required to flood such a massive area with molten rock. There’s a reason we call the formation of the Columbia River Basalts a world-class event.