... by the boxcar shape of the shoreline uplift from the last major earthquake on the fault zone. The Seattle Basin is interpreted as a flexural basin at the footwall of the Seattle fault zone. Basin stratigraphy and the regional tectonic history lead us to suggest that the Seattle fault zone initiated as a reverse...

...Samuel Y. Johnson; Christopher J. Potter; John M. Armentrout Abstract Analysis of seismic reflection data reveals that the Seattle basin (Washington) is markedly asymmetric and consists of ∼9-10 km of Eocene and younger deposits. The basin began as a discrete geologic element in the late Eocene...

... ( V S ) data at depths that capture the extent of the sedimentary column (usually greater than 30 m), which can be difficult to obtain. We acquired microtremor array data at 11 sites in the Seattle basin, Washington, and applied the wavenumber‐normalized spatial autocorrelation (SPAC) method (krSPAC...

...Catherine M. Snelson; Thomas M. Brocher; Kate C. Miller; Thomas L. Pratt; Anne M. Tréhu Abstract Recent observations indicate that the Seattle sedimentary basin, underlying Seattle and other urban centers in the Puget Lowland, Washington, amplifies long-period (1–5 sec) weak ground motions...

...Qin Li; William S. D. Wilcock; Thomas L. Pratt; Catherine M. Snelson; Thomas M. Brocher Abstract We used waveform data from the 1999 ships (Seismic Hazard Investigation of Puget Sound) seismic refraction experiment to constrain the attenuation structure of the Seattle basin, Washington State. We...

... sedimentary basin in the U.S. Pacific Northwest. For weak ground motions from the Chi-Chi earthquake, the Seattle basin amplified 0.2- to 0.8-Hz waves by factors of 8 to 16 relative to bedrock sites west of the basin. The amplification and peak frequency change during the Chi-Chi coda: the initial S -wave...

...Arthur Frankel; William Stephenson; David Carver Abstract Seismograms of local earthquakes recorded in Seattle exhibit surface waves in the Seattle basin and basin-edge focusing of S waves. Spectral ratios of S waves and later arrivals at 1 Hz for stiff-soil sites in the Seattle basin show...

...Arthur D. Frankel; David L. Carver; Robert A. Williams Abstract We used recordings of the M 6.8 Nisqually earthquake and its M L 3.4 aftershock to study site response and basin effects for 35 locations in Seattle, Washington. We determined site amplification from Fourier spectral ratios...

... that are sensitive to shallow-basin structure. This new V S model for the Seattle basin is constructed using direct observations rather than using P -wave velocity ( V P ) observations and a V P / V S ratio as all previous 3D models at this scale have been constructed. Our results reveal greater detail in the upper...