Reconnaissance geology and geologic hazards of offshore Coos Bay basin, central Oregon continental margin

Abstract

Major geologic and physiographic features of 5 the continental margin of the Pacific northwest. Correlation chart of major Tertiary units in 7 western Oregon. Area of the offshore Coos Bay basin. 11 High resolution seismic reflection record (77-05) 13 extending eastward across Heceta Bank and the adjacent shelf. High resolution seismic reflection record (78-42) 14 extending eastward from Heceta Bank across the adjacent shelf. High resolution seismic reflection record (78-32) 16 across the inner shelf north of Cape Arago. Deep penetration seismic reflection record (78-38) 17 across shelf and slope between Heceta Bank and Cape Arago. Deep penetration seismic reflection record (7$-40) 22 across inner shelf southeast of Heceta Bank. Deep penetration (a) and high resolution (b) seismic 24 reflection records (77-14) across slope northwest of Cape Arago. Deep penetration seismic reflection record (77-22) 27 across shelf and slope north of Coquille Bank. Deep penetration (a) and high resolution (b) seismic 30 reflection records (77-18) across outer shelf and slope west of Cape Arago. Deep penetration seismic reflection profile (78-30) 31 across shelf and upper slope west of Cape Arago.

Great Cascadia earthquakes and tsunamis of the past 6700 years, Coquille River estuary, southern coastal Oregon

“…The Fulmar fault deforms late Neogene and Quaternary deposits within the accretionary wedge offshore Oregon (Clarke et al, 1985;Goldfinger et al, 1992;Snavely, 1987;Tréhu et al, 1995) (Fig. 1B) and projects onshore near the Coquille estuary (Snavely, 1987).…”

Discordant 14C Ages from Buried Tidal-Marsh Soils in the Cascadia Subduction Zone, Southern Oregon Coast

“…Towns shown by cross-ruled pattern. Anticlines, synclines, and faults that produce relief on the sea floor or that deform Pleistocene marine or fluvial terraces are shown by thick lines (from Clarke et al, 1985;McInelly and Kelsey, 1990, Fig. 13).…”

“…This area includes the distal part of the active accretionary wedge of the North Americaplate ( Fig. 1; Clarke et al, 1985;Kelsey, 1990, Fig. 13).…”

Episodic tectonic subsidence of Late Holocene salt marshes, northern Oregon Central Cascadia Margin

“…Studies of relative plate motion and of recent oceanic plate seismicity indicate an oblique subduction and north-south compression of the southern Juan de Fuca plate, in accord with the northward migration of the Mendocino triple junction [Riddihough, 1984;Kelsey and Carver, 1988;Spence, 1989]. Yet Pliocene-Pleistocene imbricate thrusts and shelf fold and fault belts that dominantly trend north-south off the Oregon coast demonstrate a significant component of east-west convergent strain [Kulm and Fowler, 1974;Clarke et al, 1985]. Recent studies of deep, small-scale seismicity along the northern Cascadia the hinge line).…”