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 On-site, but not on time...  Figure 2: Map of regional tectonic setting. All along the Alaskan coastline, on the Pacific side, two of the earth's behemoth tectonic plates meet and collide, the Alaskan and the North Pacific Plates. The collision of two plates is rarely tranquil no matter how slowly the meeting takes place. Here the oceanic lithosphere of the North Pacific Plate is being forced under the continental lithosphere of the Alaskan Plate, seamounts and all, by a process called subduction. Because of Kodiak Seamount's approach into the Aleutian Trench, this seamount is literally cracking up under the stress. The resulting large cracks and fractures are known to geologists as faults. Most residents around the Pacific Rim are familiar with the unsettling events that accompany rapid faulting, earthquakes. Kodiak Seamount, southeast of Kodiak Island, belongs to the chain of the Kodiak-Bowie seamounts, and is the next one to collide with the Alaskan continental margin. Kodiak seamount has a diameter of 20 km and rises nearly 2,500 m above the surrounding ocean floor. That ought to give the lithosphere a case of indigestion. We'll have to wait until later today to see what Dr. Lonsdale and Christina have found. |
A C T I V I T I E S
• Activity 3.1a • Activity 3.1b • Diagram |
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I caught Dr. Lonsdale's graduate student Christina Massell in the galley at breakfast and she told me launch time was 8:00 a.m. Sharon and I finished breakfast and headed out to the fantail to wish Christina a good dive…But the Alvin was gone! Alvin was lowered into the ocean, just minutes ago. How disappointing.
