Both gravitational and magnetic data is used to describe the underground geology. This illustration is of gravitational readings locating structures in the South Sound. Click the image for a larger view.
A few years ago, the Steamboat Peninsula was visited by a research team from the Geologic Hazards Science Center of the U.S. Geological Survey. These researchers were using equipment to view cross-sections of geologic structures far beneath the ground. This last July, the results of this research, a paper entitled, Shallow geophysical imaging of the Olympia anomaly: An enigmatic structure in the southern Puget Lowland, Washington State, was published.
A significant benefit of this kind of research is to identify areas where stress might build and quickly release in the form of an earthquake. The Puget Sound occupies a seismically active area, located along a line where the Juan de Fuca plate is squeezed under the North America plate.
The convergence of the Juan de Fuca plate, at a rate of ~50 mm/yr (Atwater, 1970; DeMets et al., 1994), has historically produced great (magnitude, M8–9) earthquakes on the Cascadia subduction zone (e.g., Nelson et al., 2006) that pose a primary seismic hazard for the region (Petersen et al., 2002).
But what’s the story, closer to our home here on the Steamboat Peninsula?Read More
